Volume 63, Issue 4

European Union (EU) regulations on in vitro diagnostics (IVD) and on serious cross-border threats to health provide for the establishment of European Reference Laboratories (EURLs) and their harmonization and cooperation with National Reference Laboratories (NRLs). While the EURLs under the IVD Regulation will be operational by 1 October 2024, the EURLs under the Regulation on serious cross-border threats to health will be operational by January 2025. Although NRLs may have been operating for a long time on the basis of national legislation, they should now cooperate with each other and with EURLs in a network of centers of excellence for the authorization and post-market surveillance of IVDs and for the epidemiological surveillance and control of communicable diseases. The term “reference laboratory” has long been used colloquially to refer to many kinds of laboratories, regardless of their tasks, competencies, responsibilities and designation. A literature search and analysis confirmed this by showing that a considerable proportion of scientific publications in 2024 use the term “reference laboratory” inappropriately. In order to clarify the roles and functioning of EURLs and NRLs, we have evaluated the relevant current EU provisions and compared the findings with those of reference laboratories designated by other organizations, calibration (reference) laboratories and referral laboratories, which are simply referred to as “reference laboratories”. With the forthcoming implementation of the EU regulations, at least the goals of providing safe and high-quality IVDs and adequate public health surveillance for communicable diseases appear to be achievable.

Male infertility has become an important issue of global concern. Semen analysis is the cornerstone of male fertility assessment. External quality assessment (EQA) of sperm concentration, motility, and morphology is widely recognized in the world. However, over the past 34 years, the implementation of EQA for semen analysis has varied across different countries, and there is no global consensus. The goal of this paper is to first explore the overall development of EQA during this period. Secondly, it aims to discuss the extent of difference of participating laboratories in different countries. Finally, the paper examines the differences in EQA programs developed by various EQA providers in order to seek a global standard. In total, 29 papers met the inclusion criteria and were included in this review. There is inconsistent in the implementation of EQA across different countries, and there is no global consensus. Policies for EQA of semen analysis vary from country to country. Some countries mandate laboratory participation, while others permit voluntary involvement. Different EQA organizers choose different ways to calculate assigned value and acceptance limits. The coefficient of variation (CV) for each EQA item was large. The CVs of concentration, motility, morphology, and viability were 12.7–138.0 %, 17.0–127.0 %, 7–375 %, and 6–41.1 %, respectively. The results of the semen analysis varied considerably among the participating laboratories. The collaborative efforts of national policymakers, EQA organizers, and all participating laboratories are essential to improving the current situation.

In the last decades, clinical laboratories have significantly advanced their technological capabilities, through the use of interconnected systems and advanced software. Laboratory Information Systems (LIS), introduced in the 1970s, have transformed into sophisticated information technology (IT) components that integrate with various digital tools, enhancing data retrieval and exchange. However, the current capabilities of LIS are not sufficient to rapidly save the extensive data, generated during the total testing process (TTP), beyond just test results. This opinion paper discusses qualitative types of TTP data, proposing how to divide laboratory-generated information into two categories, namely metadata and peridata. Being both metadata and peridata information derived from the testing process, it is proposed that the first is useful to describe the characteristics of data, while the second is for interpretation of test results. Together with standardizing preanalytical coding, the subdivision of laboratory-generated information into metadata or peridata might enhance ML studies, also by facilitating the adherence of laboratory-derived data to the Findability, Accessibility, Interoperability, and Reusability (FAIR) principles. Finally, integrating metadata and peridata into LIS can improve data usability, support clinical utility, and advance AI model development in healthcare, emphasizing the need for standardized data management practices.

Background As the healthcare sector evolves, Artificial Intelligence’s (AI’s) potential to enhance laboratory medicine is increasingly recognized. However, the adoption rates and attitudes towards AI across European laboratories have not been comprehensively analyzed. This study aims to fill this gap by surveying European laboratory professionals to assess their current use of AI, the digital infrastructure available, and their attitudes towards future implementations. Methods We conducted a methodical survey during October 2023, distributed via EFLM mailing lists. The survey explored six key areas: general characteristics, digital equipment, access to health data, data management, AI advancements, and personal perspectives. We analyzed responses to quantify AI integration and identify barriers to its adoption. Results From 426 initial responses, 195 were considered after excluding incomplete and non-European entries. The findings revealed limited AI engagement, with significant gaps in necessary digital infrastructure and training. Only 25.6 % of laboratories reported ongoing AI projects. Major barriers included inadequate digital tools, restricted access to comprehensive data, and a lack of AI-related skills among personnel. Notably, a substantial interest in AI training was expressed, indicating a demand for educational initiatives. Conclusions Despite the recognized potential of AI to revolutionize laboratory medicine by enhancing diagnostic accuracy and efficiency, European laboratories face substantial challenges. This survey highlights a critical need for strategic investments in educational programs and infrastructure improvements to support AI integration in laboratory medicine across Europe. Future efforts should focus on enhancing data accessibility, upgrading technological tools, and expanding AI training and literacy among professionals. In response, our working group plans to develop and make available online training materials to meet this growing educational demand.

The presented guidelines are an update of the position paper, endorsed by the International Osteoporosis Foundation (IOF), on nomenclature of bone markers published over 2 decades ago. Novel insight into bone biology and pathophysiology of bone disorders has highlighted the increasing relevance of new and known mediators implicated in various aspects of bone metabolism. This updated guideline proposes the nomenclature Bone Status Indices (BSI) as the comprehensive classification rather than bone turnover markers, bone markers, metabolic markers of bone turnover or metabolic markers of bone turnover, that are currently in use for the implicated molecules. On behalf of the IFCC Committee on Bone Metabolism and the Joint IOF Working Group and IFCC Committee on Bone Metabolism, the authors propose standardized nomenclature, abbreviations and measurement units for the bone status indices.

Objectives Serum cystatin C (CysC) is a reliable and ideal endogenous marker for accurately assessing early changes in glomerular filtration rate (GFR), surpassing the limitations of creatinine-based estimated GFR. To improve the precision of GFR calculation, the development of strategies for accurately measuring serum CysC is crucial. Methods In this study, the full-length CysC pure product and fully recombinant 15 N-labeled CysC internal standard were subjected to protein cleavage. Subsequently, an LC-MS/MS method was developed for the absolute quantification of serum CysC. The traceability of the method was assigned calibrator using the amino acid reference measurement procedure (RMP). It involved calibrating the instrument using an amino acid reference material with known amino acid concentrations for calibration and comparison purposes. Results The total imprecision of the method was determined to be ≤8.2 %, and a lower functional limit of quantification (LLoQ) was achieved. The recoveries ranged from 97.36 to 103.26 %. The relative bias between this candidate RMP for measurement of ERM-DA471-IFCC and the target value was 1.74 %. The linearity response was observed within the concentration range of 0.21–10.13 mg/L, with a high R 2 value of 0.999. The results obtained using our method was consistent with those obtained using other certified RMPs. Conclusions With the establishment of this highly selective and accurate serum CysC measurement method, it is now possible to assess the correlation between immunoassay results of serum CysC and the intended target when discrepancies are suspected in the clinical setting.

Objectives To evaluate the efficacy, safety and efficiency performances related to the introduction of innovative traceability platforms and integrated blood collection systems, for the improvement of a total testing process, thus also assessing the economic and organizational sustainability of these innovative technologies. Methods A mixed-method approach was utilized. A key-performance indicators dashboard was created based on a narrative literature review and expert consensus and was assessed through a real-life data collection from the University Hospital of Padova, Italy, comparing three scenarios over time (2013, 2016, 2019) with varying levels of technological integration. The economic and organizational sustainability was determined considering all the activities performed from the tube check-in to the validation of the results, with the integration of the management of the prevalent errors occurred during the process. Results The introduction of integrated venous blood collection and full sample traceability systems resulted in significant improvements in laboratory performance. Errors in samples collected in inappropriate tubes decreased by 42 %, mislabelled samples by 47 %, and samples with irregularities by 100 %. Economic analysis revealed a cost saving of 12.7 % per tube, equating to a total saving of 447,263.80 € over a 12-month period. Organizational efficiency improved with a reduction of 13,061.95 h in time spent on sample management, allowing for increased laboratory capacity and throughput. Conclusions Results revealed the strategic relevance of introducing integrated venous blood collection and full sample traceability systems, within the Laboratory setting, with a real-life demonstration of TLA economic and organizational sustainability, generating an overall improvement of the process efficiency.

Objectives There is a lack of analyte stability data in whole blood (WB). The aim of this study was to determine the allowable delay in WB processing for lactate dehydrogenase (LDH), folate, vitamin B12, iron and phosphate measurement. The stability of LDH, folate and vitamin B12 was also assessed in stored serum at clinically relevant time points. Methods Blood was taken from n=10 volunteers into Sarstedt serum gel tubes. We assessed stability in WB at room temperature up to 24 h, and stability in refrigerated serum up to 72 h. Mean percentage deviation at each time point was compared to criteria for minimum allowable bias. Results Results produced from one individual were removed due to discordant results, leaving n=9 specimens at each time point. Stability of folate and phosphate was variable in WB across 24 h, but was deemed to be clinically acceptable. LDH was unstable in WB, iron was stable for at least 12 h, and vitamin B12 and ferritin were acceptable for up to 24 h. Serum LDH, folate and vitamin B12 all demonstrated acceptable stability in refrigerated serum stored for up to 72 h. Conclusions Blood should ideally be centrifuged within 7 h for phosphate, LDH and folate, and 12 h for iron. However, for phosphate, folate and iron, there is likely to be little clinical impact if serum separation is delayed up to 24 h. Further research is needed to assess LDH stability in WB at 0–12 h, but changes are minimal at 12 h. All other analytes assessed showed acceptable stability across the time-points tested.

Objectives This study examined the comparability of venous and capillary blood samples with regard to routine chemistry analytes. Methods Venous and capillary blood samples were collected from adult patients to assess comparability of alanine transaminase, albumin, alkaline phosphatase, apolipoprotein B, aspartate aminotransferase, total bilirubin, calcium, chloride, creatin kinase, creatinine, C-reactive protein, ferritin, folic acid, free T4, gamma glutamyltransferase, glucose, high density lipoprotein cholesterol, iron, lipase, lipoprotein a, magnesium, phosphate, postassium, prostate specific antigen, sodium, total cholesterol, total protein, transferrin, triglycerides, thyroid stimulating hormone, urate, urea, vitamin B12 and 25-hydroxyvitamin-D3. Furthermore, hemolysis-icterus-lipemia Index (HIL-Index) was measured for all samples. All measurements were performed using the Siemens Atellica ® CH or IH Analyzer. Deming regression analysis and mean relative differences between venous and capillary measurements of each analyte were contrasted with the desirable total allowable error (TEa) and Clinical Laboratory Improvement Amendments (CLIA) 2024 proposed acceptance limits for proficiency testing. Results Deming regression and mean relative differences demonstrated excellent comparability between venous and capillary samples for most measured analytes. Conclusions Capillary and venous samples showed comparable results for almost all studied chemistry analytes. Of the 33 studied analytes for which TEa criteria where available, 30 met TEa criteria. CLIA 2024 criteria where available for 29 of the studied analytes of which only glucose did not meet the criteria. In conclusion, capillary blood draw is a suitable alternative for venous blood sampling for measuring most of the investigated analytes. This benefits patients with fear of needles and might pave the way for remote self-sampling.

Objectives Serum total bile acid (TBA) levels are frequently assessed in clinical routine for the early detection of hepatobiliary dysfunction. However, the comparability of current 5th-generation TBA cycle assays based on 3α-hydroxysteroid dehydrogenase (3α-HSD) and their ability to quantify individual bile acids has not been systematically addressed. Methods Patient serum samples (n=60) across the diagnostically relevant TBA range (1–200 μmol/L) were analyzed using five TBA routine assays from Abbott, DiaSys, Diazyme, Beijing Strong (BSBE) and Randox on the same analyzer (BioMajesty ® JCA-BM6010/C). The assays were compared using Passing-Bablok regression and the recovery of 11 individual BAs was evaluated against RP-HPLC-MS/MS as non-enzymatic reference method. Results Despite excellent correlation (Spearman r ≥0.99), the assays showed proportional differences (slope) ranging from 0.99 (BSBE/Randox) to 1.24 (Abbott/DiaSys). The assays showed considerable deviation in the recovery of competitor’s calibrators and controls, and large heterogeneity in the recovery of individual BAs, with mean deviations from reference value between 13 % (DiaSys) and 42 % (Abbott). CA and TCA were measured most accurately and consistently, whereas GCA, CDCA, DCA, UDCA, and conjugates were over- or undermeasured to varying degrees. Conclusions The linear relationship and constant proportional bias between all five routine assays enable the harmonization of TBA measurements up to 60 μmol/L. However, for patient samples with high TBA levels and disease-specific overrepresentation of individual BAs, harmonization will require: i) optimized reaction conditions to equalize substrate specificity, and ii) calibration to a common, commutable reference material with well-defined BA composition instead of internal standards spiked with different BAs.

Objectives Xylazine is a potent sedative used in veterinary medicine. Recently, recreational drugs such as fentanyl have been found to contain xylazine, increasing the risk of respiratory depression and death. Despite a similar presentation to opioid overdose, patients who ingest xylazine do not respond to treatment with Narcan. Therefore, rapid detection of xylazine could improve patient management and prevent adverse outcomes. Methods We evaluated the XYL500 one-step xylazine drug of abuse test for its ability to detect xylazine in 152 urine samples from patients on chronic opioid therapy for pain management or in treatment for substance use disorder. Results were compared to LC-MS/MS as the reference method. Precision, cross-reactivity, interference and stability studies were performed. Results Pooled patient samples were consistently negative or positive when tested five times on the same day and over three days of testing. The diagnostic sensitivity, specificity and accuracy of the XYL500 assay were 74, 98, and 82 % respectively, as compared with LC-MS/MS. XYL500 detected 77 of the 104 LC-MS/MS positive samples identified in our initial evaluation, including some that contained low levels of xylazine (n=8), <10 ng/mL. Minimal cross-reactivity with other opioid analgesics and commonly encountered drugs was seen with only one false positive result. Interferences by common urine contaminants were negligible. Specimens were stable up to 160 days refrigerated and up to 80 days at room temperature. Conclusions XYL500 allows for rapid detection of xylazine, illustrating its utility in monitoring patients who ingested recreational drugs containing the additive, xylazine, and its potential to improve patient management.

Objectives Subarachnoid haemorrhage (SAH) has a high morbidity and mortality and requires prompt diagnosis. In patients with negative findings on computed-tomogram of the brain (CT-Brain) cerebrospinal fluid (CSF)-xanthochromia is considered the test of choice if performed 12 h or more after symptom onset. We audited the accuracy, usefulness and timing of CSF-xanthochromia testing and the interpretation of equivocal CSF-xanthochromia findings. We also investigated mortality outcomes for defined subsets of patients. Methods A retrospective audit of CSF-xanthochromia tests over 8 years was performed. The service uses the revised UK-NEQAS (United Kingdom National External Quality Assessment Service) method. Results We analysed 543 cases (F=299, median age 44yrs) with 19 cases (3.5 %) having SAH. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CSF-xanthochromia testing were 100 , 98.1, 65.9, 100 % respectively (equivocal results were counted as positives). 280 cases (F=153, median age 43yrs) had LP performed more than 24 h after the onset of headache (median time to LP=72 h). The sensitivity and specificity of the CSF-xanthochromia were 100 and 97.4 % in this group with NPV 100 % and PPV 66.6 %. 183 (65.4 %) CSF-xanthochromia negative cases in this subgroup had follow up data and survived without SAH occurring in the 12 months follow up. Conclusions In this study, supported by followup outcome data, we show that CSF-xanthochromia testing using the revised UK-NEQAS method is fit-for-purpose for the use as a second line test to exclude SAH in patients with negative CT-brain including delayed presentation more than 24 h after headache onset.

Objectives Quantitative protein mass spectrometry (MS) is ideally suited for precision diagnostics and for reference standardization of protein analytes. At the Leiden Apolipoprotein Reference Laboratory we apply MS strategies to obtain detailed insight into the protein-to-peptide conversion in order to verify that quantifier peptides are not partly concealed in miscleaved protein backbone. Methods Apolipoprotein(a) (apo(a)) was digested in a non-optimal manner to enhance the number of miscleaved peptides that were identified by high resolution liquid chromatography tandem-MS measurements. The protein-to-peptide conversion was carefully mapped with specific attention for miscleaved peptides that contain an apo(a) quantifier peptide. Four different isotopologues of each apo(a)-quantifier peptide were applied to evaluate linearity of internal peptide standards during measurement of specific real-life samples. Results Two apo(a) quantifier peptides that were concealed in two different miscleaved peptides were included into a multiple reaction monitoring list in our targeted MS-based apo(a) quantifications to alert for potential protein digestion discrepancies. The presence of miscleaved peptides could be ruled out when applying our candidate reference measurement procedure (RMP) for apo(a) quantification. Conclusions These data further corroborate the validity of our apo(a) candidate RMP as higher order method for certification of commercial Lp(a) tests that is endorsed by the International Federation of Clinical Chemistry and Laboratory Medicine. MS-based molecular detection and quantification of heterogeneous apo(a) proteoforms will allow manufacturers’ transitioning from confounded lipoprotein(a) [Lp(a)] mass levels into accurate molar apo(a) levels.

Objectives Early rheumatoid arthritis (RA) detection is crucial for improving patient prognosis. Anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factors (RF) support RA diagnosis but are undetectable in ∼20 % of cases. Recently, antibodies against mutated citrullinated vimentin (anti-MCV) and detection of 14-3-3 eta have emerged with implications for preclinical RA diagnosis and monitoring treatment. The objective of this study was to assess the clinical performance of anti-MCV antibodies and 14-3-3 eta in RA and to compare it to current RA criteria anti-CCP and RF markers, individually and in combination. Methods A retrospective chart review of 326 subjects submitted for RA serology testing identified 134 RA positive and 192 RA negative disease control individuals. Fifty healthy controls specimens were also included. Performance of anti-MCV and 14-3-3 eta, alone and combined with CCP3.1 and RF, was assessed. Results Anti-MCV had a sensitivity of 71 % and a specificity of 92 %. 14-3-3 eta had a sensitivity of 43 % and a specificity of 90 %. In comparison, CCP3.1 and RF displayed a sensitivity of 79 % and 84 % and a specificity of 92 % and 61 %, respectively. ROC curve analysis demonstrated CCP3.1 and anti-MCV had superior diagnostic performance compared to RF and 14-3-3 eta. In our cohort, anti-MCV and 14-3-3 eta failed to identify seronegative RA patients. Different combinations of double antibody positivity increased specificity at the cost of lost sensitivity. Conclusions Individually, 14-3-3 eta, anti-MCV and CCP3.1 assays had ≥90 % specificity in diagnosed RA patients, with better sensitivities for anti-MCV and CCP3.1 than 14-3-3 eta. Overall diagnostic performance of anti-MCV was similar to CCP3.1 and RF, all of which outperformed 14-3-3 eta in our cohort.

Objectives This study aimed to determine the clinical significance of Krebs von den Lungen-6 (KL-6), surfactant proteins A (SP-A) and D (SP-D) in the evaluation and management of interstitial lung disease (ILD). Methods Serum KL-6, SP-A, SP-D levels were measured in 122 unique consecutive patients referred for connective tissue disease (CTD) associated ILD (CTD-ILD) autoantibodies and 120 “healthy” controls. Patients’ charts were retrospectively reviewed and categorized as ILD and non-ILD or CTD-ILD and other ILD. All biomarkers were evaluated for diagnosis and moderate vs. severe ILD based on high-resolution computed tomography (HRCT). Results ILD was diagnosed in 52 % (n=64) and non-ILD in 48 % (n=58). ILD patients were categorized as other ILD (61 %, n=39) or CTD-ILD (39 %, n=25). Patients with ILD had significantly elevated levels of SP-A (p<0.02), KL-6 or SP-D (both p<0.0001) when compared to those with non-ILD. The mean levels of all biomarkers were significantly elevated levels in the ILD compared to non-ILD group (p<0.0001). No significant difference in biomarker levels between CTD-ILD and other ILD groups (p≥0.900). Biomarkers had comparable specificities (89–93 %) however; sensitivities were variable at 75 , 77 and 17 % for KL-6, SP-D and SP-A, respectively. Combination of KL-6 and SP-D yielded comparable diagnostic accuracy to all biomarkers with median levels significantly higher in patients with severe vs. mild disease. Conclusions KL-6 and SP-D levels are elevated in ILD and therefore contribute to the diagnosis and risk stratification for patient management.

Objectives Congenital adrenal hyperplasia (CAH) is a rare, inherited disorder of adrenal steroid synthesis. In many countries it is part of the neonatal screening program enabling early diagnosis and treatment. In case of an abnormal neonatal screening result or when other differences of sexual development (DSD) are suspected, measurement of serum steroid hormones using liquid chromatography coupled to mass spectrometry (LC-MS/MS) is needed for further diagnosis. However, reliable age- and sex-specific reference intervals (RIs) for serum steroid hormones during the neonatal period are missing. We therefore aimed to establish LC-MS/MS based RIs for serum steroid hormones in neonates. Methods Serum was obtained from healthy term neonates at two time points: 130 samples at day 3–8 ( T1 , time of the neonatal screening) and 126 samples at day 13–15 ( T2,  two weeks old). Concentrations of cortisol, cortisone, corticosterone, 11-deoxycortisol, 21-deoxycortisol, 11-deoxycorticosterone, testosterone, androstenedione, and 17-hydroxyprogesterone (17-OHP) were measured using LC-MS/MS. Results RIs (in nmol/L) were established for T1 and T2 : cortisone (19.3–215;18.0–212), cortisol (10.0–407;8.4–446), corticosterone (<31;<50), 11-deoxycortisol (0.73–4.6;0.70–3.6), 17-OHP (<4.9;<5.1), androstenedione (0.3–1.8;0.3–2.7), 11-deoxycorticosterone (<0.2;<0.2), and 21-deoxycortisol (<1;<1), respectively. Testosterone differed between boys and girls: RIs at T1 and T2 for boys were 0.27–4.3 and 0.63–13.9, and for girls<0.30 and <0.47, respectively. Conclusions We established LC-MS/MS based RIs for cortisol, cortisone, corticosterone, 11-deoxycortisol, 21-deoxycortisol, 11-deoxycorticosterone, testosterone, androstenedione, and 17-OHP in neonates in the first and second week of life.

Objectives To provide age- and sex-specific paediatric reference intervals (RIs) for 13 haematological parameters analysed on Sysmex XN-9000 and compare different methods for estimating RIs after indirect sampling. Methods Via the Danish Laboratory Information System, we conducted a population-based study. We identified samples from children aged 0–18 years analysed at Aarhus University Hospital from 2019 to 2023, including samples from general practitioners only. Information about all parameters were available for all samples via linkage to the local laboratory middleware. Then, we applied two different methods. First, we excluded potential pathological samples by predefined criteria: if the child had other abnormal blood measurements at date of request, or had a blood sample of any type analysed in the period two months before to two months after. We estimated RIs stratified by age- and sex using the non-parametric percentile method. Second, we used refineR (an open source automated algorithm) to exclude pathological samples and for RI estimation. Finally, we compared our data to results from a study using the direct method. Results We identified 22,786 samples. After exclusion by predefined criteria, the population comprised 10,199 samples from 8,736 children (57 % of samples were from females and median age was 13 years). We estimated RIs for red blood cell, white blood cell and platelet indices. The two different methods showed agreement. Furthermore, our data provided results comparable to direct sampling. Conclusions Our study provided age- and sex-specific paediatric RIs for 13 haematology parameters useful for laboratories worldwide. RIs were robust using different methods in the framework of indirect sampling. Finally, our data showed agreement with the direct method, indicating that indirect sampling could be useful for establishing RIs on haematology parameters in the future.

Objectives The present multicenter study was designed to evaluate the analytical performance and the 99th percentile value of the reference healthy population i.e., 99th percentile upper reference limit of the MAGLUMI ® CLIA high-sensitivity cardiac troponin I (hs-cTnI) method. Methods Analytical performances and the 99th percentile URL value of the chemi-luminescent-immuno-assay (CLIA) method were evaluated using validated and standardized experimental protocols. Two cohorts including healthy adult individuals were enrolled. The first one included 989 blood donor volunteers (489 women and 500 men) aged 18–70 years (mean age 43 years, interquartile range 31–54 years). The second population included 47 healthy individuals (31 women and 16 men, mean age 78 years, interquartile range 73–81 years) aged≥71 years. Results The distributions of hs-cTnI levels in both sexes are highly right-skewed, and men show significantly (p=0.0028) higher biomarker values than women. Moreover, in both sexes the hs-cTnI levels progressively increase after the 55 years. In the multivariate analysis (n=958), hs-cTnI was found to be significantly associated to NT-proBNP (p<0.0001), sex (p<0.0001) and BMI (p=0.0424). The 99th percentile URL values, calculated using the bootstrap method in the total reference heathy population (age≥18 years), were: Females (n=521): 5.93 ng/L (CI 95 % 5.29–8.48), Males (n=516): 9.79 ng/L (CI 95 % 6.37–17.41 ng/L), Total Population (n=1,037): 7.18 ng/L (CI 6.08–12.20 ng/L). Conclusions The MAGLUMI CLIA method met all the criteria for an hs-cTnI assay recommended by international guidelines. The hs-cTnI values measured with the CLIA method are higher in men compared to women at the same age, and also progressively increase after the age>55 years.

Objectives Hemoglobin A 1c (HbA 1c ) is an established tool in the diagnosis and follow-up of patients with diabetes. However, in some patients the interpretation of HbA 1c results faces challenges due to additional biological variation or non-steady-state conditions. This study aimed to demonstrate the value of the L-HbA 1c /HbA 1c -ratio as a tool to flag HbA 1c results, which do not reflect average glycemia “as expected” in routine clinical practice. Methods A total of 450 samples of unique patients were selected based on the L-HbA 1c /HbA 1c -ratio determined on a Tosoh G8 analyzer resulting in a group with a high ratio (≥0.50), a group with a low ratio (≤0.27) and a group with a normal ratio (0.27–0.50). The relationship between HbA 1c and glycemic markers (fructosamine and random glucose) was established for all ratio groups. In a smaller cohort of type 1 diabetes patients, continuous glucose monitoring was used as glycemic marker. Results The correlation between HbA 1c and glycemia (random glucose and fructosamine) differs significantly between the ratio groups. For the same HbA 1c level random glucose levels and protein-corrected fructosamine are higher in the high ratio group compared to the normal and low ratio groups, pointing to an underestimation of the glycemic status by HbA 1c in patients with high L-HbA 1c /HbA 1c -ratios. The sensitivity of a high ratio to predict a glycation gap lower than −1.5 NGSP units is 82 % and the specificity is 65 %. Conclusions The results of this study reveal the usefulness of the L-HbA 1c /HbA 1c -ratio as an additional check in the interpretation of HbA 1c results in order to detect HbA 1c results not reflecting glycemia as expected.