10^th Annual Meeting of the Austrian Society for Laboratory Medicine and Clinical Chemistry (ÖGLMKC)

A02

Gender-Specific Bile Acid Profiles in Non-Alcoholic Fatty Liver Disease

H Mangge, V Matzka, J Fitzinger, G Rodriguez-Blanco, M Herrmann, A Borenich, R Stauber, E Aigner

Medical University of Graz, Clinical Institute of Medical and Chemical Laboratory Diagnostics (CIMCL), Graz, Austria

Background: Non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. A main cause is an obesogenic, so-called Western lifestyle. NAFLD follows a long, unperceived course, and ends potentially fatally. Early diagnosis of aggressive subtypes may save lives. So far, non-invasive means of detection are limited. Metabolomics may give insight into pathogenic processes to identify useful new biomarkers.

Methods: In this study, we measured bile acids (BA) in the plasma of 45 adult NAFLD and 57 alcohol-associated liver disease (ALD) patients and 103 healthy controls with targeted mass spectrometry. We focused on gender-related bile acid production pathology in NAFLD and ALD.

Results: Compared to healthy controls, women with NAFLD had significantly higher concentrations of total BA, total cholic (CA), total chenodeoxycholic (CDCA), total glycine-conjugated, and total non-12-a-OH BA. The BA subtypes glycocholic (GCA) and glycochenodeoxycholic (GCDCA), were elevated only in women with NAFLD. In contrast, men with NAFLD had no significantly altered total BA fractions. The BA subtypes GCA, glycodeoxycholic (GDCA), glycolithocholic (GLCA), lithocholic (LCA), taurolithocholic (TLCA), and tauroursodeoxy-cholic acid (TUDCA) were elevated, while CA was significantly decreased. In female and male NAFLD patients, except ursodeoxycholic acid (UDC), all total BA correlated significantly positively in both sexes with the ELF score. In ALD, only males showed significant correlations with the ELF score exceptive for total UDC. In NAFLD, total BA, total primary BA, total secondary BA, total free secondary BA, total CA, total CDCA, total taurine conjugated, total glycine conjugated, total 12-a-OH, and total non-12-a-OH were significantly higher in cases of a high enhanced liver fibrosis (ELF) score above 9.8. In ALD, total UDC was additionally elevated. Between NAFLD with and without NASH, we found no significant differences.

Conclusion: Our data show gender-specific BA profiles in NAFLD and markedly different BA patterns in ALD. Women with NAFLD had more severe cholestasis. Men may better compensate fat storage-driven bile acid dynamics, indicated by higher levels of taurine-conjugated BA, which associate with beneficial functions.

Keywords: bile acid profiles, NAFLD, ALD, gender differences

Reference: Nutrients 2024; 16:250 PMID: 38257143

Bile acid nomenclature: total cholic (CA), total chenodeoxycholic (CDCA), glycocholic (GCA), glycocholic (GCA), glycolithocholic (GLCA), lithocholic (LCA), taurolithocholic (TLCA), tauroursodeoxycholic acid (TUDCA), ursodeoxycholic acid (UDC)

A04

Evaluation of the in vitro stability of drugs of abuse in blood samples under different storage conditions

K Paschuk, A Hausch, Y Herschel-Aydinli, T Mueller

Hospital Voecklabruck,Department of Laboratory Medicine, Voecklabruck, Austria

Introduction: Toxicological tests play a central role in clinical and forensic investigations of drug abuse. An adequate pre-analytical phase must be ensured for the correct determination of drug levels in blood. The aim of this study was therefore to evaluate the in vitro stability of different drugs in blood using the biochip array technology as the measurement method.

Methods: Plasma concentrations of methylenedioxymethamphetamine (MDMA), tricyclic antidepressants (TCA), oxazepam, tetrahydrocannabinol (THC) and ethyl glucuronide (EtG) were determined from 59 blood samples 1) immediately after blood collection, 2) after storage of whole blood for six hours at room temperature, 3) after storage of whole blood for 24 hours at room temperature and 4) after storage of plasma for 24 hours at -80°C. Plasma levels of the five drugs of abuse were measured using the Evidence MultiSTAT DOA ToxPlex Blood Assay (Randox Laboratories). According to the concept of “accaptable change limits” (ACL), analytes were considered stable if the mean analyte recovery at a given time was >50%.

Results: After applying the analyte stability limit, all five drug classes were stable for 24 hours after storage of whole blood at room temperature and plasma at -80°C. At the different storage conditions, the maximum mean percentage deviation was 9% for MDMA, 4% for TCA, 4% for oxazepam, 16% for THC and 8% for EtG.

Conclusion: For a correct determination of the blood concentrations of MDMA, TCA, oxazepam, THC and EtG, the blood samples do not have to be analyzed immediately after sampling when using the Randox Biochip Array technology, but can be stored for up to 24 hours at room temperature prior to measurement. Consequently, sample storage (including any necessary sample transportation) appear to be unproblematic in clinical practice.

A05

P-tau217 in blood as a screening marker for Alzheimer’s disease

J Telser ¹ , S Hutter ¹ , T Lung ¹ , M Thalmann ¹ , M Risch ¹ , L Risch ^1,2,3

¹ Dr. Risch Medical Laboratory, Buchs, Switzerland

² Private University in the Principality of Liechtenstein, Triesen, Liechtenstein

³ University of Bern, University Institute of Clinical Chemistry, Bern, Switzerland

Background and aims: The potential of disease-modifying therapies for Alzheimer’s disease (AD) has stimulated interest in the development of minimally invasive testing for identification of at-risk individuals. Accordingly, identification of blood-based biomarkers is paramount. The discovery of tau phosphorylated at threonine217 (p-tau217) may provide a turning point in AD diagnosis. This study aims to evaluate serum p-tau217 as a routine parameter.

Material and methods: 184 individuals with available Erlangen Scores (ES) measured in their cerebrospinal fluid on the Lumipulse platform from Fujirebio in the Medical Laboratory Dr. Risch were included in the study. On the same platform, serum p-tau217 was measured. Results were compared to the obtained cerebrospinal fluid results.

Results: Serum p-tau217 concentrations increase progressively with higher ES, ranging from a mean of 0.104 pg/ml at ES 0 to 0.414 pg/ml at ES 4 (ES1: 0.139 pg/ml, ES 2: 0.166 pg/ml, ES 3: 0.218 pg/ml). Notably, concentrations at ES 4 (probable AD) are significantly higher than those at Scores 0–3 (improbable to possible AD). Classifying the test dichotomously by ES - where a score of 4 indicates disease presence and scores of 0–3 reflect its absence or an intermediate state - the resulting AUC is 0.883. Using a threshold of > 0.225 pg/ml yields a sensitivity of 82% and a specificity of 83%. Lowering the threshold to > 0.102 pg/ml increases sensitivity to 97% and reduces specificity to 52%, while raising it to > 0.332 pg/ml enhances specificity to 96% and lowers sensitivity to 51%.

Conclusion: Serum p-tau217, a promising biomarker for AD, is intended to be used as a standalone screening tool in our laboratory. Due to its strong diagnostic accuracy, it can be used as a preliminary step before employing traditional diagnostic methods, such as cerebrospinal fluid analysis or imaging techniques.

A08

CA 125 Dynamics, Associations with Heart Failure Readouts, and Response to Empagliflozin Following Acute Myocardial Infarction

AM Hassan ¹ , F Aziz ^2,3 , N Tripolt ^2,3 , M Herrmann ¹ , H Sourij ^2,3 , D von Lewinski ⁴

Medical University of Graz, Graz, Austria

¹ Clinical Institute for Medical and Chemical Laboratory Diagnostics

² Department of Internal Medicine, Division of Endocrinology and Diabetology

³ Interdisciplinary Metabolic Medicine Trials Unit

⁴ Department of Internal Medicine, Division of Cardiology

Introduction: CA 125 has gained attention as a possible biomarker for heart failure (HF), but little is known about how it changes over time, its response to sodium-glucose co-transporter 2 (SGLT2) inhibitors, and its connection to other HF indicators following acute myocardial infarction (AMI).

Methods: CA 125 levels were measured in frozen samples from the EMMY (Empagliflozin in Myocardial Infarction) study, a randomized, double-blind, placebo-controlled trial investigating the effects of empagliflozin on myocardial recovery in patients with AMI. A total of 418 patients were included in this analysis, with 207 receiving empagliflozin and 211 receiving placebo. Measurements were performed using a chemiluminescent microparticle immunoassay (Allinity i CA 125 II, Abbott GmbH, Wien, Austria; produced for Abbott by Fujirebio Diagnostics, Pennsylvania, USA). Robust linear mixed-effects models (R-LMEM) were applied to evaluate how CA 125 evolved over 26 weeks, its response to empagliflozin therapy, and its relationships with established HF markers post-AMI.

Results: CA 125 levels exhibited minor variations at six weeks before dropping below the baseline at 26 weeks. The administration of empagliflozin did not lead to a statistically significant change in log-transformed CA 125 levels. However, log-transformed CA 125 showed strong associations with key HF indicators, including log-transformed N-terminal pro-brain natriuretic peptide (NT-proBNP) (estimate: 0.31; p < 0.001), left ventricular ejection fraction (LVEF) (estimate: -2.23; p < 0.001), left ventricular end-systolic diameter (LVESD) (estimate: 0.90; p = 0.029), left ventricular end-systolic volume (LVESV) (estimate: 4.51; p < 0.001), and the E/e′ ratio (estimate: 0.51; p = 0.002). Notably, empagliflozin altered the correlations between log-transformed CA 125 and both log-transformed NT-proBNP (estimate: 0.43; p = 0.024) and the E/e′ ratio (estimate: 0.91; p = 0.015).

Conclusion: While CA 125 levels remained largely unaffected by empagliflozin, the drug influenced its relationship with NT-proBNP and the E/e′ ratio, suggesting potential interactions that warrant further study.

A11

Validation of age-dependent reference intervals for thyroid hormones on ALINITY I using three different indirect methods

Y Gao ¹ , A Meyer ² , R Müller ² , M Hoffmann ² , W Huf ³ , S Demyanets ¹

¹ Clinic Hietzing, Department of Laboratory Medicine, Vienna, Austria

² Abbott GmbH, Wiesbaden, Germany,

³ Karl Landsteiner Institute for Clinical Risk Management, Vienna, Austria

Background: Diagnosis of patients or evaluation of their status involve frequently data from laboratory investigations, which are interpreted using reference intervals (RIs). Ideally, RIs should be derived from a matched healthy reference population, which is difficult to achieve in practice, especially for special populations like pediatric or geriatric cohorts.

Methods: According to the ISO 15189:2022 laboratories are required to verify their reference intervals conferring to their served patient population, pre-analytics, and methods used. To validate the reference intervals for thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) on the Alinity i analyzer in a setting with geriatric focus, RIs were calculated using retrospective datasets employing a modified Hoffmann (RefLim)-, Truncated Maximum Likelihood-, and refineR-method using more than 20.000 and 5.000 individual results for TSH and fT3/fT4 respectively.

Results: The indirect RIs were generally in line with the manufacturer’s intervals for TSH and FT4, though results partitioned for age supported a tighter reference range for younger ages and a positive shift of the upper reference limits in older adults, especially for FT4 in line with manufacturer. For FT3 we did observe an age-dependent decrease in patients above 60 years.

Conclusion: Though agreement between the calculated and the manufacturer RIs was generally acceptable, the analysis of age and gender effects showed that geriatric patient groups (>60) would benefit from dedicated RIs, which can also be described with direct RI methods. Indirect RI methods seem to be a possible tool to validate the laboratory RIs, but also offer the possibility to better address subgroups, like geriatric patients, through dedicated RIs. As the global aging population continues to grow, the definition of Ris for older subgroups allowed more accurate interpretation of thyroid status and personalized therapy.

A12

Evaluation of the first blood based CE-IVD certified Test for Morbus Alzheimer – A real life experience

G Endler ^1,2 , B Mühl ² , G Engstler ²

¹ Medical Faculty, Sigmund Freud Private University Vienna, Vienna Austria

² Gruppenpraxis Labors.at, Vienna Austria

Objectives: The accelerated development of disease modifying therapies targeting β amyloid for the treatment of Alzheimer’s disease has increased the need for rapid and reliable biomarkers for the rapid screening and diagnosis of the disease. Current diagnostic biomarkers (amyloid PET-Scan or CSF analysis for Aβ42/40 and P-tau181) are limited to specialised institutions due to high costs and low availability. Recently, the first CE-IVD certified blood based test measuring amyloid ß42/40 ratio in plasma, has become available in Europe, allowing screening for Alzheimer in patients with clinical signs of dementia in Europe. We firstly report the application of this test in a large outpatient laboratory in Vienna.

Methods: Determination of plasma amyloid ß42/40 ratio was performed by fully automated high-sensitivity chemiluminescence enzyme (HISCL) immunoassay. This is a magnetic bead enhanced capture chemiluminescence assay allowing high precision measurements in minimal quantities. Additionally, a standardized pre-analytical pathway for the K₂EDTA sample tubes was established to ensure reliable measurement.

Results: A Total of 84 individuals (46 females, 38 males, mean age 72 years) could be included. The strict preanalytical standardisation resulted in >90% valid results, only 4 samples had to be excluded due to inappropriate material. Up to now ∼50% of the patients had an amyloid ß42/40 ratio >0,102 with a low probability of Alzheimer disease, 34% had a ratio <0,093 indicating a high probability of a ß amyloid pathology, and 16% of the results within the grey zone of the assay.

Conclusions: Plasma ß42/40 ratio has proven its practical applicability in outpatient routine and represents a valid screening tool in outpatient care. Due to its excellent negative predictive value, this assay allows valid exclusion of individuals without ß amyloid pathology.

A13

LDL Target value Archievment in hypercholesterolemic individuals in eastern Austria – a retrospective crossectional study

F Endler ^1,2 , G Endler ^1,2 , M Exner ²

¹ Medical Faculty, Sigmund Freud Private University Vienna, Vienna Austria

² Gruppenpraxis Labors.at, Vienna Austria

Background: Cardiovascular diseases are the main cause of death worldwide, not only in the Western world. Among the 200 known different cardiovascular risk factors elevated LDL (Low density Lipoprotein) and Lipoprotein (a) (Lp(a) level account for ∼30 percent of the overall cardiovascular risk.

Since lipid lowering therapy is relatively cheap and widely available and LDL target values are well established, we aimed to evaluate the proportion of individuals achieving low risk target levels (<116mg/dl) in a large cross-sectional retrospective study in Vienna.

Patients and Methods: A total of 1 596 532 individuals had a first time lipid measurement in a large outpatient laboratory in Vienna, Austria (Labors.at, Vienna) between 2015 and 2024. Of these 268 374 had LDL levels above low risk target values (>116 mg/dl) and a follow up measurement one year after first time assessment. Lp(a) levels were evaluated if measured. The database query was completely anonymized without any personal data except gender and age in years to ensure privacy of the participants. To avoid bias through multiple measurement only the first available LDL was included.

Results: Only 26.6% (95% CI: 26.4%-26.7%) of the hypercholesterolemic patients reached LDL within the low risk target value (<116 mg/dl) after one year. Lp(a) was assessed only in 1.9% of all individuals.

Discussion: While a great proportion of the Austrian population had their LDL status measured, only one in four individuals with hypercholesteremia reached at least target levels for low cardiovascular risk after one year. Only 1.9% had their Lp(a) measured at least once in lifetime. To our knowledge, this is the largest cross-sectional real life evaluation of this question in Austria revealing a great potential for improving primary cardiovascular prevention.

A15

Prevalence of gestational diabetes depending on socioeconomic status - a retrospective study

V Piribauer ¹ , AK Porth ² , G Endler ³

¹ Medical Faculty, Sigmund Freud Private University Vienna, Vienna Austria

² Medizinische Universität Wien

³ Gruppenpraxis Labors.at, Vienna Austria

Background: Gestational diabetes mellitus (GDM) is a glucose tolerance disorder that manifests itself during pregnancy. Worldwide, it is estimated that between 3.0% and 16.5% of all pregnancies are affected. In Austria, it is diagnosed as part of a screening program between the 24th and 28th week of pregnancy using an oral glucose tolerance test (OGTT). Methods: The aim of this retrospective data analysis was to investigate whether the socioeconomic status (SES) of pregnant women influences the prevalence of GDM between 2015 and 2023. A total of 65,353 women were categorized based on the average income of their residential district and their age at the time of pregnancy. A chi-square test was performed to assess the association between socioeconomic status and GDM prevalence. Additionally, a logistic regression analysis was conducted to evaluate the effect of maternal age on the risk of developing GDM.

Results: The mean age of first-time pregnant women was 30.7 years (95% CI [30.66–30.75], SD: 5.476, median: 31.0 years). GDM was diagnosed in 6,988 women (11.0%; 95% CI [10.76–11.24], SD: 0.12). A statistically significant association between GDM prevalence and SES was observed (χ² = 40.046; p < 0.001). The prevalence of GDM was higher in the low-income group (13.2%; 95% CI [12.62–13.71]) compared to the middle-income group (11.7%; 95% CI [11.26–12.06]) and the high-income group (9.8%; 95% CI [8.85–10.72]). Furthermore, maternal age was identified as a significant risk factor for GDM (χ² = 270.599; p < 0.001). Women aged 35–49 years had a higher GDM prevalence (14.4%; 95% CI [13.90–14.99]) compared to those aged 20–34 years (9.9%; 95% CI [9.64–10.18]) and 14–19 years (6.9%; 95% CI [5.57–8.51]). Logistic regression analysis (χ² = 367.371; p < 0.001) demonstrated that the risk of developing GDM increased with advancing maternal age during pregnancy (Exp(B) = 1.046).

Conclusion: A clear association between SES and the prevalence of GDM was identified. Furthermore, the analysis confirms that maternal age is a significant risk factor for the development of GDM. These findings align with existing scientific literature, reinforcing previously established associations. The findings highlight the importance of addressing social and economic disparities in healthcare to effectively reduce the risk of pregnancy-related conditions.

A18

Implementation of the kappa free light chain index in clinical routine

M Egger ¹ , J Lanschützer ¹ , P Schmid ¹ , T Hofer ² , A Black ¹ , B Dieplinger ¹

¹ Konventhospital Barmherzige Brueder and Ordensklinikum Linz, Department of Laboratory Medicine

² Konventhospital Barmherzige Brueder, Department of Neurology Linz, Austria

Background: Kappa free light chain (k-FLC) index has been increasingly recognized for its diagnostic potential in multiple sclerosis (MS) and clinically isolated syndrome (CIS). The aim of this study was to evaluate the diagnostic performance of k-FLC index in comparison to oligoclonal bands (OCB), the current gold standard for the detection of intrathecal immunoglobulin G synthesis, in a large consecutive cohort of patients from clinical routine.

Methods: k-FLC index and OCB were determined in paired serum and cerebrospinal fluid samples of patients diagnosed with MS (n=85), CIS (n=9), Inflammatory Neurological Disease Controls (INDC, n=125), Non-Inflammatory Neurological Disease Controls (NINDC, n=274) and in Symptomatic Controls (SC, n=205). An optimal cut-off for k-FLC index was derived from ROC-curve analysis and diagnostic performance was compared to OCB measurement. A simple stepwise test algorithm with the k-FLC index as screening test was identified to reduce further OCB testing.

Results: k-FLC index was higher in MS/CIS patients (n=94) when compared with INDC/NINDC/SC patients (n=604). The optimal cut-off for the diagnosis of MS/CIS from ROC-curve analysis was >7,5 k-FLC index and showed a better sensitivity (94,7% vs. 87,2%) and a slightly less specificity of (92,7% vs. 95%) than OCB. Using the diagnostic k-FLC index cut-off >7,5 additional 7 out of 12 OCB negative MS/CIS patients had been identified. With a decision threshold of k-FLC index >3,5 for further OCB testing, OCB testing has been reduced by 65% in this study cohort.

Conclusions: In the present study the diagnostic k-FLC index cut-off of >7.5 showed similar diagnostic accuracy for MS/CIS patients as OCB and was even able to identify some additional false negative cases from OCB testing. A proposed stepwise testing approach using a lower k-FLC index of >3,5 as decision threshold for further OCB testing, would substantially reduce OCB testing in clinical routine.

A01

The role of post-translationally modified collagen in atherothrombosis

T Koller, T Afonyushkin, M Oszvar-Kozma, S Taqi, M Hoke, CJ Binder

Medical University of Vienna, Clinical Institute of Laboratory Medicine, Vienna, Austria

Background & Aims: Collagen, a main driver of atherothrombosis, can be post-translationally modified. Little is known about how this alters its coagulatory properties. Carotid artery plaque collagen was recently described to carry malondialdehyde (MDA) modifications, a type of oxidation specific epitope (OSE) formed in the oxidative plaque environment. Levels of anti-OSE IgMs inversely correlate with myocardial infarction, suggesting a role of OSEs in coagulation. We hypothesize that OSE-modification of collagen exacerbates its coagulatory potential which is inhibited by anti-OSE IgM antibodies.

Methods; The impact of MDA modification was tested using platelet assays (Multiplate aggregation, PAC1/P-Selectin expression, light transmission aggregometry), a flow chamber model, and a mouse pulmonary thrombosis model. MDA-specific natural IgM antibody’s ability to inhibit MDA-modified collagen induced coagulation was assessed in vitro and in vivo. Mechanistically, von Willebrand Factor (vWF) binding was assessed by ELISA. Finally, patients with carotid artery disease were tested for MDA-collagen IgM levels and vWF levels.

Results; MDA modification of collagen increased platelet activation. LR04, an MDA specific monoclonal IgM, but not an isotype IgM reduced the procoagulatory potential of MDA-collagen. Ex vivo, LR04 delayed clot formation on an MDA collagen coated surface under flow. Similarly, LR04 but not an isotype control protected from mouse pulmonary thrombosis triggered by injection of MDA collagen. LR04 reduced vWF binding to MDA-collagen and consequently reduced platelet activation. Importantly, high plasma levels of IgM antibodies with specificity for MDA collagen were associated with significantly increased survival in patients with carotid artery disease and protected from vWF-associated increased risk of cardiovascular death.

Conclusion; We describe a novel pro-thrombotic mechanism occurring during atherothrombosis. MDA-modified collagen increases its pro-coagulatory potency, potentially worsening atherothrombotic events. Anti-MDA collagen IgM antibodies in turn protect from these deleterious effects by inhibiting vWF binding to MDA collagen, consequently reducing platelet aggregation resulting in better cardiovascular outcomes for patients.

A10

Case report of lupus-like inhibitor in psychiatric setting: interdisciplinary diagnostic approach

¹ Y Gao, ² M Wolf, ¹ H Sterner, ³ M Fellinger, ¹ R Hauer, ¹ S Demyanets

¹ Clinic Hietzing, Department of Laboratory Medicine, Vienna, Austria

² Technoclone GmbH, Vienna, Austria

³ Clinic Hietzing, Second Department of Psychiatry and Psychotherapy, Vienna, Austria

Background: Lupus Anticoagulant (LAC) is an antiphospholipid antibody that interferes with phospholipid (PL)-dependent coagulation tests, therefore leading to prolonged clotting times without corresponding clinical bleeding symptoms. However, LAC can also be detected in healthy or at least asymptomatic individuals or in the presence of other autoimmune diseases, infections, or malignancies. Additionally, lupus-like anticoagulants were described under certain medications. From the laboratory perspective, LAC and lupus-like inhibitors present significant challenges in coagulation testing as it can lead to false low factor activity levels when measured using one-step clotting assays. Chromogenic factor assays are usually not affected by LACs because the high sample predilution minimizes the influence of phospholipids on the reaction.

Results: We present the case of a 50-year-old female who was admitted to the hospital with schizophrenia on medication with lorazepam, olanzapine and aripiprazole and had no signs or history of bleeding or thrombophilia. Routine laboratory analysis at admission showed a significantly prolonged activated partial thromboplastin time (aPTT, SynthaSil on ACL Top 500, Werfen) of 77 sec, leading to a thorough evaluation of potential causes. The intrinsic coagulation factors activity using the one-step clotting assay demonstrated near-undetectable levels for factors VIII, IX, XI, and XII. Further investigation revealed an elevated LAC ratio of 2.2 using the diluted Russel Viper venom test (DRVVT). Mixing studies on aPTT assays as well as on LA Screen showed no normalization. Another aPTT based LAC testing (aPTT Siron LS/aPTT Siron LIS, Technoclone) showed an elevated normalized ratio and no normalization in the mixing test. Chromogenic factor VIII assay (Technochrom FVIII 2G on Ceveron s100, Technoclone) showed normal activity of factor VIII of 130%. IgMs of Anti-cardiolipin antibodies as well as Beta-2- Glycoprotein antibodies were elevated whereas the IgGs were within the normal range (Acl AcuStar, Werfen). To have an overview of the overall coagulation potential thrombin generation assay (TGA) was performed using Technothrombin TGA RC Low and showed unaffected values.

Conclusion: This case report serves as a critical reminder for laboratory professionals and clinicians to be vigilant when interpreting coagulation test results in patients with prolonged aPTT in preanalytical normal haemostatic status, and reminds about the importance of direct communication between the laboratory and clinicians concerning the medication, anamnesis and clinical status of the patients.

A16

Impact of K2- ethylenediaminetetraacetate (EDTA) contamination in citrated plasma on ADAMTS13 activity testing and its detection

L Brunelli, A Egger, L Loacker, M Anliker, A Griesmacher, *C Irsara

University Hospital of Innsbruck, Central Institute for Medical and Chemical Laboratory Diagnostics (ZIMCL), Innsbruck, Austria

Background: Contamination of serum, lithium-heparinized and citrated blood with ethylenediaminetetraacetate (EDTA) can affect the results of multiple tests, among them ‘a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13’ (ADAMTS13) activity. Reporting falsely low ADAMTS13 activities can lead to thrombotic thrombocytopenic purpura (TTP) misdiagnoses, posing serious risk to patient safety. In this study, we examined the impact of different concentrations of dipotassium-(K ₂ )EDTA in citrated blood on ADAMTS13 activity testing and explored how contamination can be detected by measuring routine chemistry and coagulation parameters.

Materials and methods: Using remnant blood from 20 apparently healthy individuals, we mimicked a ‘real world’ scenario of K ₂ EDTA contamination by adding different proportions of autologous whole blood from the K ₂ EDTA tube into the citrated tube (1-50% K ₂ EDTA). We measured Technoclone TECHNOFLUOR ADAMTS13 activity, along with activated partial thromboplastin time (aPTT), prothrombin time (PT), potassium (K), sodium (Na), chloride (Cl), calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe), and phosphate.

Results: ADAMTS13 activity decreased significantly with increasing K ₂ EDTA concentration, reaching values suggestive for TTP in the severely contaminated samples (≥25%K ₂ EDTA). Spurious contamination (≤2%K ₂ EDTA) could be indirectly detected by measuring Zn and Cu, and gross contamination (≥25%K ₂ EDTA) was identified also using Ca, Mg and K as indicators.

Conclusion: We demonstrate that gross K ₂ EDTA contamination of citrated blood results in critically false-low ADAMTS13 activity values, and that contamination can be substantially excluded through the simultaneous measurement of routine biochemical parameters. We encourage all laboratories to exclude EDTA contamination of samples prior to ADAMTS13 testing.

A03

Genome-scale genome engineering to enhance the therapeutic potential of T cells

M Kerler, MY Shlei, H Fasching, T Frey, K Schmetterer, R Schmidt

Medical University of Vienna, Department of Laboratory Medicine, Vienna, Austria

T cell-based immunotherapies have emerged as powerful tools in treating various malignancies including acute leukemia, multiple myeloma and lymphoma. However, exhaustion, senescence and late differentiation states characterized by reduced self-renewal and proliferative potential limit their therapeutic efficacy. Here, we employed genome-wide CRISPR activation (CRISPRa) screens in primary human T cells to systematically identify factors promoting cellular fitness. Our screening approach encompassed over 120,000 sgRNAs targeting approximately 20,000 genes with up to 6 guides per gene, evaluating their impact on T cell differentiation state and function. Through this comprehensive analysis, we identified novel regulatory networks controlling T cell fitness and discovered previously uncharacterized factors that modulate T cell differentiation. Key hits were validated through arrayed CRISPRa studies and functional assays, demonstrating significant alterations in differentiation-associated phenotypes. Mechanistic studies revealed that these factors primarily regulate pathways involved in T cell fate decisions and maintenance of early differentiation states. Our findings provide new insights into T cell biology and identify promising therapeutic targets for enhancing the efficacy of cellular immunotherapy.

A17

Mitochondrial DNA copy number in leukocytes predicts prostate cancer survival

¹ T Langsenlehner, ¹ K Paal, ¹ E-M Thurner, ² M Langmüller, ² R Sternat, ² W. Renner

Purpose: Low mitochondrial DNA copy number (mtCN) in leukocytes is a predictor of all-cause mortality, independent of age and sex. For malignant diseases, results about the prognostic value of leukocyte mtCN have been conflicting. Aim of the present study was to analyze the prognostic value of mtCN for long-term prostate cancer survival.

Methods: Blood samples of prostate cancer patients were obtained before initiation of radiotherapy. Relative mitochondrial DNA copy number was determined by a quantitative polymerase chain reaction method in 662 patients with prostate cancer. Main outcome was overall survival.

Results: During a follow-up time of 120 months, 218 (32.9%) patients died. In a univariate Cox regression analysis, higher mtDNA z-score was significantly associated with lower overall mortality (hazard ratio 0.83, 95% confidence interval 0.72 – 0.96; p = 0.009). In a multivariate Cox regression model including age at diagnosis, androgen deprivation therapy, and risk group (based on PSA level, GS, and T stage), higher mtCN z-score remained a significant predictor of lower overall mortality (hazard ratio 0.85, 95% confidence interval 0.74 – 0.98; p = 0.029).

Conclusions: High leukocyte mtCN predicts better overall survival in patients with prostate cancer.

A21

Machine learning based thalassemia prediction – model development and over one year experience from routine diagnostics

AP Piehler, C Creatore, HT Mevik, G Hoermann, EW Axelsen

MLL Munich Leukemia Laboratory, Munich, Germany

Introduction: Thalassemias are among the most common inherited blood disorders worldwide, and early identification of carriers is important for genetic counseling of couples at risk. The present study describes the development of a machine learning based prediction model and shows results from its application in clinical routine diagnostics.

Methods: Hemoglobinopathy test results from 18.848 individuals were retrospectively extracted from the database of a large European laboratory, Fürst Medical Laboratory, Norway. An eXtreme Gradient Boosting (XGB) model was trained to identify positive thalassemia cases using 11 parameters, including gender, age, erythrocyte indices and clinical chemistry results. After validation, hyperparameter tuning and evaluation of the results by hematology and AI experts, the algorithm was put into production to evaluate all incoming samples to the clinical routine laboratory. Positive prediction of thalassemia resulted in an active recommendation to the requesting physician for further investigation, negative thalassemia screening results were not communicated.

Results: On the total training set, the algorithm showed the following performance metrics in predicting the presence of thalassemia: Sensitivity 0.94, specificity 0.91, accuracy 0.91, and F1-score 0.90.

In the first eight months of its application in routine diagnostics (10/2023-05/2024), thalassemia testing was performed in 2048 samples. In these data unknown to the model, prediction performance was as follows: Sensitivity 0.88, specificity 0.81, accuracy 0.80, F1-score 0.79.

Implementing feedback from requesting physicians, the prediction threshold of the model was adjusted after the initial period from 0.5 to 0.7 to increase specificity and precision. In the following six months (06/2024-12/2024), the model evaluated more than 600.000 samples and predicted thalassemia in 6657 cases. Of these samples, further thalassemia testing was requested and performed in 783 cases, and a diagnosis of thalassemia made in 84% (n=657). In the same period, the laboratory received 1574 samples for hemoglobinopathy testing with no previous recommendation for thalassemia testing (i.e. no or a negative previous prediction from the algorithm). Of these samples, only 36% (n=566) were tested positive for thalassemia.

Conclusions: Machine learning based prediction of thalassemia is a feasible and effective means of identifying thalassemia patients in high-throughput routine medical laboratories.

A06

Evaluating Multilineage Involvement in B-ALL/LBL with BCR::ABL1 Fusion using a newly developed FACS/PLA Panel at the General Hospital Vienna - Medical University Campus

V Oberhauser

General Hospital Vienna - Medical University Campus, Department of Laboratory Medicine, Vienna, Austria

Background: B-lymphoblastic leukemia/lymphoma (B-ALL/LBL) with BCR::ABL1 fusion, also known as Philadelphia chromosome-positive (Ph+) B-ALL, is a genetically defined hematologic malignancy characterized by the t(9;22) translocation. In most Ph+ B-ALL cases, the BCR::ABL1 fusion is confined to B-lineage leukemic cells; however, in some instances, it originates from a primitive hematopoietic stem cell (HSC), leading to its presence across multiple hematopoietic lineages - a phenomenon known as multilineage involvement. Ph+ B-ALL/LBL with multilineage involvement has been associated with a more favorable prognosis, as current therapeutic strategies, including tyrosine kinase inhibitors in combination with chemotherapy, are more effective in eliminating HSCs than common lymphoid progenitor cells. However, the detection of multilineage involvement in Ph+ B-ALL/LBL remains challenging, requiring the integration of multiple assessment methods e.g. fluorescence-activated cell sorting (FACS) followed by molecular analyses. More recently, Löf and colleagues developed a novel method for detection and enumeration of cells harboring the BCR::ABL1 fusion at the protein level in a cohort of BCR::ABL1-positive Chronic myeloid leukemia (CML) patients. This new approach combines the in situ proximity ligation assay (in situ PLA) with flow cytometry as a readout, referred to as ‚PLA-flow‘.

Objective: This study aims to develop and validate a novel multiparametric flow cytometry-based proximity ligation assay (FACS/PLA) to enable single-assay detection of BCR::ABL1 across different hematopoietic cell lineages. By integrating lineage-specific fluorescent markers (e.g., CD19 for B lymphocytes, CD3 for T lymphocytes, CD33/CD14 for myeloid and monocytic cells) with PLA probes targeting the BCR::ABL1 fusion protein, this method seeks to improve the efficiency and accuracy of multilineage detection in Ph+ B-ALL/LBL.

Methods: The research involves two phases: (1) assay validation using well-characterized BCR::ABL1-positive cell lines expressing distinct lineage markers, and (2) application of the FACS/PLA panel to longitudinal patient samples collected over two years at the General Hospital Vienna. This approach will assess the prevalence and dynamics of multilineage involvement in patients with Ph+ B-ALL/LBL and CML. The panel’s diagnostic accuracy and analytical validity will be evaluated in terms of specificity, sensitivity, reproducibility, and concordance with quantitative RT-PCR, the current gold-standard method.

Expected Outcomes: Successful implementation of the FACS/PLA panel is expected to provide a reliable tool for detecting and monitoring multilineage involvement in Ph+ B-ALL/LBL, facilitating clinical decision-making by enabling more precise identification of patients who may benefit from targeted therapies and hematopoietic stem cell transplantation. Conclusion: This study presents an innovative approach for detecting multilineage involvement in Ph+ B-ALL/LBL, with potential applications in both clinical diagnostics and leukemia research. By streamlining the detection process, the FACS/PLA panel may provide a more comprehensive and efficient tool for identifying the hematopoietic lineages affected by the BCR::ABL1 fusion, ultimately contributing to personalized treatment strategies for patients with this hematologic malignancy.

A07

Cellular expression of PD-1, PD-L1 and CTL4A in patients with JAK2 ^V617F mutated myeloproliferative disorders

¹ C Winkler, ¹ M Anliker, ² S Schmidt, ² C Feistritzer, ³ B Höchsmann, ³ H Schrezenmeier, ⁴ A Siller, ¹ A Griesmacher, ¹ L Loacker

¹ University Hospital of Innsbruck, Central Institute of Clinical and Chemical Laboratory Diagnostics, Innsbruck, Austria

² Medical University of Innsbruck, Department of Internal Medicine V, Hematology and Oncology, Innsbruck, Austria

³ University of Ulm, Institute of Transfusion Medicine , Ulm, Germany and Institute of Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service and University Hospital of Ulm, Ulm, Germany

⁴ University Hospital Innsbruck, Tirol Kliniken GmbH, Central Institute for Blood Transfusion and Immunology, Innsbruck, Austria

Objectives: The acquired, somatic JAK2^V617F mutation is the most common molecular aberration in patients with myeloproliferative neoplasms (MPN) and also significantly involved in the regulation of T cell immunity. PD-1, PD-L1 and CTL4A are key immune checkpoint regulators that are elevated in patients with solid tumors, infectious diseases and chronic inflammation. We hypothesized that JAK2^V617F modulates the expression of checkpoint inhibitors.

Methods: The surface expression of PD-L1, PD-1 and CTL4A on peripheral blood leukocytes was determined by flow cytometry in 27 patients with JAK2^V617F positive MPN and in a control group of 26 healthy individuals and analyzed by immune checkpoint and leukocyte subpopulation. In addition, the concentration of soluble PD-L1 (sPD-L1) in plasma was examined by ELISA.

Results: PD-1, PD-L1 and CTL4A are significantly overexpressed on the surface of granulocytes in JAK2-positive patients compared to the control group. Soluble PD-L1 (sPD-L1) is also significantly elevated in the plasma of JAK2 positive patients and increases with decreased renal function. In CD8+ T-cells and CD4+ T-cells there is a significant negative correlation between PD-1 expression or sPD-L1 concentration and their corresponding absolute cell count.

Conclusion: Our study shows a significant increase of immune checkpoint regulators on the cellular surface as well as the soluble PD-L1 form in JAK2 mutated patients compared to the control group. Increased activation of the JAK2/STAT signaling pathway by JAK2^V617F appears to be a mechanism of reduced immune activation in patients with MPN. Immune checkpoint inhibition might therefore represent a potential additional therapeutic target in this disease group.

A19

Flow cytometric CAR T cell monitoring after treatment with anti-BCMA CAR T cells

¹ K Deutsch-Biedermann, ¹ J Gruber, ¹ C Kimbacher, ¹ I Herbring, ² S Machherndl-Spandl, ¹ B Dieplinger, ¹ K Hefler-Frischmuth

¹ Konventhospital Barmherzige Brueder Linz and Ordensklinikum Linz, Department of Laboratory Medicine, Linz, Austria

² Ordensklinikum Linz Elisabethinen, Department of Internal Medicine I: Hematology with Stem Cell Transplantation, Hemostaseology and Medical Oncology, Linz, Austria

Background: CAR T cell therapy is an effective treatment option for patients with relapsed refractory multiple myeloma. A close monitoring during the early phase after CAR T cell infusion is important for response evaluation. In this study we set up a flow cytometric panel for quantification of anti-BCMA CAR T cells. The aim was to find out how the amount of anti-BCMA CAR T cells varies over time to evaluate the most suitable time points for monitoring anti-BCMA CAR T cells in routine diagnostics.

Methods: Peripheral blood samples from 16 patients with multiple myeloma receiving anti-BCMA CAR T cell therapy were included in this study over a period of 10 months. Quantification of anti-BCMA CAR T cells was performed on day 7, day 14 and day 28 after CAR T cell infusion. 12 of the 16 patients were additionally measured within 8 to 10 weeks and within 11 to 14 weeks after CAR T cell infusion, and 7 patients within 20 to 28 weeks after CAR T cell infusion. 50µl of EDTA-blood samples were stained with fluorochrome antibodies against BCMA CAR T (Miltenyi Biotech), CD4, CD14, CD3, CD8 and CD45 (Beckman Coulter). After 15 minutes of incubation, samples were lysed for 15 minutes and centrifuged for 5 min at 300xg. The cell pellet underwent one more wash- and centrifugation step before it was resuspended in 500µl PBS. Before the sample was measured with a DxFlex flow cytometer (Beckman Coulter), it was incubated with 5µl of 7-AAD for 5 minutes. A FMO-control was included. A total of 500.000 cells were acquired for both the anti-BCMA CAR T- and the FMO sample. The absolute number of anti-BCMA CAR T cells were calculated from the differential blood count values.

Results: The median number of anti-BCMA CAR T cells per µl peripheral blood on day 7 after CAR T cell infusion was 57 cells/µl (range 2- 2107), on day 14 the median number was 216 cells/µl (range 21-1574) and on day 28 the median number was 19 cells/µl (range 5-567). The median number of anti-BCMA CAR T cells within 8 to 10 weeks was 5 cells/µl (range 0-138), within 11 to 14 weeks one cell/µl (range 0-54) and within 20 to 28 weeks 5 cells/µl (range 0-153) after CAR T cell infusion.

Conclusions: In our study we set up and evaluated the suitability of a flow cytometric panel for monitoring anti-BCMA CAR T cells from peripheral blood samples of patients with relapsed refractory multiple myeloma undergoing a CAR T cell therapy. We could show that the amount of anti-BCMA CAR T cells reached the highest amounts on day 7 and 14 after infusion, which is in line with previous studies. This emphasizes the suitability of our flow cytometric panel for anti-BCMA CAR T cell monitoring especially within the first two weeks after CAR T cell infusion. Further research is needed for long term flow cytometric response evaluation in combination with clinical outcomes.

A20

Flow cytometric CAR T cell monitoring after treatment with anti-CD19 CAR T cells

¹ K Deutsch-Biedermann, ¹ J Gruber, ¹ C Kimbacher, ¹ I Herbring, ² S Machherndl-Spandl, ¹ B Dieplinger, ¹ K Hefler-Frischmuth

¹ Konventhospital Barmherzige Brueder Linz and Ordensklinikum Linz, Department of Laboratory Medicine, Linz, Austria

² Ordensklinikum Linz Elisabethinen, Department of Internal Medicine I: Hematology with Stem Cell Transplantation, Hemostaseology and Medical Oncology, Linz, Austria

Background: CAR T cell therapy is an effective treatment option for relapsed/ refractory B-cell lymphomas. A close monitoring during the early phase after CAR T cell infusion is important for response evaluation. In this study we set up a flow cytometric panel for quantification of anti-CD19 CAR T cells. The aim was to find out how the amount of anti-CD19 CAR T cells varies over time to evaluate the most suitable time points for monitoring anti-CD19 CAR T cells in routine diagnostics.

Methods: Peripheral blood samples from 22 patients with relapsed/ refractory B-cell lymphoma receiving anti-CD19 CAR T cell therapy were included in this study over a period of 16 months. Quantification of anti-CD19 CAR T cells was performed on day 7, day 14 and day 28 after CAR T cell infusion. 10 of the 22 patients were additionally measured within 6 to 12 weeks, 11 within 13 to 18 weeks and 7 within 19 to 53 weeks after CAR T cell infusion. 50µl of EDTA-blood samples were stained with fluorochrome antibodies against CD19 CAR T (Miltenyi Biotech), CD4, CD14, CD3, CD8 and CD45 (Beckman Coulter). After 15 minutes of incubation, samples were lysed for 15 minutes and centrifuged for 5 min at 300xg. The cell pellet underwent one more wash- and centrifugation step before it was resuspended in 500µl PBS. Before the sample was measured with a DxFlex flow cytometer (Beckman Coulter), it was incubated with 5µl of 7-AAD for 5 minutes. A FMO-control was included. A total of 500.000 cells were acquired for both the anti-CD19 CAR T- and the FMO sample. The absolute number of anti-CD19 CAR T cells were calculated from the differential blood count values.

Results: The median number of anti-CD19 CAR T cells per µl peripheral blood on day 7 after CAR T cell infusion was 72 cells/µl (range 0- 672), on day 14 the median number was 40 cells/µl (range 0-683) and on day 28 the median number was one cell/µl (range 0-368). No anti-CD19 CAR T cells were detectable in 60% of the samples measured within 6 to 12 weeks, in 64% measured within 13 to 18 weeks and in 71% measured within 19 to 53 weeks after CAR T cell infusion.

Conclusions: In our study we set up and evaluated the suitability of a flow cytometric panel for monitoring anti-CD19 CAR T cells from peripheral blood samples of patients with relapsed/ refractory B-cell lymphoma undergoing a CAR T cell therapy. We could show that the amount of anti-CD19 CAR T cells reached the highest amounts on day 7 and 14 after infusion, which is in line with previous studies. This emphasizes the suitability of our flow cytometric panel for anti-CD19 CAR T cell monitoring especially within the first two weeks after CAR T cell infusion. Further research is needed for long term flow cytometric response evaluation in combination with clinical outcomes.

A14

Establishment of a liquid-chromatography tandem mass-spectrometry method for six vitamin D metabolites to investigate the vitamin D status in patients with kidney disease

¹ S Zelzer, ¹ K Sobolewska, ^1,2 D Enko, ¹ P Kieslinger, ¹ H Elsayed, ¹ M Herrmann

¹ Medical University of Graz, Clinical Institute of Medical and Chemical Laboratory Diagnostics, Graz, Austria

² General Hospital Hochsteiermark, Institute of Clinical Chemistry and Laboratory Medicine, Austria

Introduction: The 1,25-dihydroxy-vitamin-D (1,25(OH)2D) is the most active metabolite which is mainly produced in the kidney via 1α-hydroxylase. This vitamin D metabolite can be further hydroxylated to 1,24,25-trihydroxyvitamin D (1,24,25(OH)3D) with the 24-hydroxylase. Expression studies of the CYP24A1 gene in rats, which encodes for 24-hydroxylase, have shown that the activity are not congruent in low renal function [1]. Therefore, the concentration of 1,25(OH)2D, 1,24,25(OH)3D and the 1,24,25(OH)3D-to-1,25(OH)2D vitamin D metabolite ratio (1,25-VMR) is of great interest for the vitamin D status in patients with kidney disease.

Methods: We extended and optimized our earlier published liquid chromatography-tandem mass-spectrometry (LC-MS/MS) vitamin D metabolite method [2] with these two vitamin D compounds. This method, including the metabolites 25(OH)D3, 25(OH)D2, 24,25(OH)2D, 25,26(OH)2D, 1,25(OH)2D and 1,24,25(OH)3D, is based on protein precipitation, liquid-liquid-extraction and derivatization. Chromatographic separation was achieved on a Nexera UHPLC from SHIMADZU (Kyoto, Japan) using a Kinetex® 5 μm F5 100 Å LC column (150×4.6 mm, Phenomenex, Torrance, CA, USA) with gradient elution. A SCIEX QTRAP 6500 triple quadrupole instrument (Applied Biosystems, Framingham, MA, USA) with electrospray ionisation (ESI) was employed for detection.

Results: The analytical performance of our new method showed the following results: Calibration curve ranged between 15.6 and 500 pg/mL for 1,25(OH)2D and 1,24,25(OH)D3D with a correlation coefficient between 0.997 and 0.999. The limit of detection (LOD) for both new metabolites is 3.9 pg/mL and the limit of quantification (LOQ, lowest concentration where the assay gives an inter-assay imprecision of <15%) is 7.8 pg/mL. Recovery varied from 78.4 to 105.5% for all metabolites. The intra-assay coefficients of variation (CVs) ranged between 1.2 and 9.4%, the inter-assay CVs between 1.2 and 11.3%. Three probands with an identified 24-hydroxylase deficiency showed a 1,25(OH)2D concentration between 362 and 509 pg/mL. The metabolite 1,24,25(OH)3D concentration ranged between 4.1 and 7.5 pg/mL and the 1,25-VMR was between 1.1. and 1.6%.

Conclusion: This extended method for the measurement of six vitamin D metabolites showed a good and reliable analytical performance for all tested vitamin D metabolites. The establishment of this vitamin D assay provides further information regarding the impact of the kidneys on the vitamin D status.

References

1. Turner ME, Rowsell TS, Kaufmann M, Norman PA, Neville K, Sarabia S, White CA, Petkovich M, Jones G, Adams MA, Holden RM. J Steroid Biochem Mol Biol. 2023;226:106207.

2. Zelzer S, Meinitzer A, Enko D, Simstich S, Le Goff C, Cavalier E, Herrmann M, Goessler W. J Chromatogr B Analyt Technol Biomed Life Sci. 2020;1158:122394.

A09

Analysis of real-world data for assessing the performance of Treponema pallidum serology tests

A Hoffmann, B Neißl-Thonhauser

LKH Universitätsklinkium Graz, Klinisches Institut für Medizinische und Chemische Labordiagnostik (KIMCL), Graz, Austria

Introduction: With a steady rise of Syphilis cases and resulting laboratory samples, updates of the laboratory work-up are needed. This is supported by new fully automated Treponema pallidum serology tests with increased diagnostic performance. To ensure a high sensitivity and specificity within the new workflow, a detailed data analysis was performed.

Methods: From 1^st January 2023 to 30^th September 2024 12505 blood samples were analysed for syphilis serology in our laboratory. They were tested using Alinity i Syphilis TP Reagent Kit (Abbott Laboratories, USA; n=12454), Treponema pallidum IgM ELISA (DRG Diagnostics GmbH, Germany; n=6281), RPR Test Kit (Bio-Rad Laboratories Inc., UK; n=8631) and RecomLine Treponema IgG and IgM Blot (Mikrogen GmbH, Germany; n=1472).

Results: Here a comparison of the tests is presented with a focus on concordance of results and workflow optimisation.

The Alinity i Syphilis TP Reagent Kit shows a low rate of not measurable samples (n=0/12454; 0%) and a low rate of borderline results (n=1; 0.008%). Over all the concordance with RecomLine IgG and IgM Blot is high.

Regarding the fear of missing very early syphilis cases in many samples a RPR test was performed. We can show a very high rate of concordant negative results for Alinity i Syphilis TP Reagent Kit and the RPR (3720/3723; 99.92%).

Due to the good performance of the Alinity I Syphilis TP Reagent Kit we rearranged our workflow with a focus on reducing manually test procedures and sparing tests. A reduction of RPR test by over 80%, and a reduction of IgG/IgM Blots by > 50% could be established by an unchanged high testing performance.

Conclusion: This analysis of existing laboratory data is a good example how testing strategies can be optimized by continuing high diagnostic accuracy.

Additionally we can demonstrate that higher sensitivity and accuracy of modern tests have to be considered even in the area of syphilis serology.