Volume 61, Issue 1

Saliva is a complex biological fluid with a variety of biomolecules, such as DNA, RNA, proteins, metabolites and microbiota, which can be used for the screening and diagnosis of many diseases. In addition, saliva has the characteristics of simple collection, non-invasive and convenient storage, which gives it the potential to replace blood as a new main body of fluid biopsy, and it is an excellent biological diagnostic fluid. This review integrates recent studies and summarizes the research contents of salivaomics and the research progress of saliva in early diagnosis of oral and systemic diseases. This review aims to explore the value and prospect of saliva diagnosis in clinical application.

The term “emerging technology” (ET) is used extensively, and there are numerous definitions offered, but to our knowledge, none specifically encompass the field of laboratory medicine. An ET definition that incorporates the overarching IFCC aim of “Advancing excellence in laboratory medicine to support healthcare worldwide” would clarify discussions. We discuss key aspects of the term “emerging technology(ies)” as it applies to laboratory medicine with a view to laying the foundations for a practical definition for the profession and propose the definition of an ET as “ An analytical method or device that by virtue of its stage of development, translation into broad routine clinical practice, or geographical adoption and implementation has the potential to add value to clinical diagnostics ”.

Laboratory automation in clinical laboratories has made enormous differences in patient outcomes, with a wide range of tests now available that are accurate and have a rapid turnaround. Total laboratory automation (TLA) has mechanised tube handling, sample preparation and storage in general chemistry, immunoassay, haematology, and microbiology and removed most of the tedious tasks involved in those processes. However, there are still many tasks that must be performed by humans who monitor the automation lines. We are seeing an increase in the complexity of the automated laboratory through further platform consolidation and expansion of the reach of molecular genetics into the core laboratory space. This will likely require rapid implementation of enhanced real time quality control measures and these solutions will generate a significantly greater number of failure flags. To capitalise on the benefits that an improved quality control process can deliver, it will be important to ensure that an automation process is implemented simultaneously with enhanced, real time quality control measures and auto-verification of patient samples in middleware. Therefore, it appears that the best solution may be to automate those critical decisions that still require human intervention and therefore include quality control as an integral part of total laboratory automation.

The EFLM recommends not to implement the race-free Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation in European laboratories and to keep the 2009 version of the CKD-EPI equation, without applying a race correction factor. This recommendation is completely in line with a recent Editorial published by the European Renal Association who has also proposed to change to a novel equation only when it has considerably better performance, trying to reach global consensus before implementing such a new glomerular filtration rate (GFR) estimation equation. In Europe, this equation could be for instance the new European Kidney Function Consortium (EKFC) equation, which is population-specific, developed from European cohorts and accurate from infants to the older old. Beyond serum creatinine, the estimating equations based on cystatin C will probably gain in popularity, especially because cystatin C seems independent of race. Finally, we must keep in mind that all GFR equations remain an estimation of GFR, especially rough at the individual level. Measuring GFR with a reference method, such as iohexol clearance, remains indicated in specific patients and/or specific situations, and here also, the role of the clinical laboratories is central and should still evolve positively in the future.

Background Standardized results for laboratory tests are particularly important when their interpretation depends on fixed medical practice guidelines or common reference intervals. The medical laboratory community has developed a roadmap for an infrastructure to achieve standardized test results described in the International Organization for Standardization standard 17511:2020 In vitro diagnostic medical devices – Requirements for establishing metrological traceability of values assigned to calibrators, trueness control materials and human samples . Among the challenges to implementing metrological traceability are the availability of fit-for-purpose matrix-based certified reference materials (CRMs) and requirements for regulatory review that differ among countries. A workshop in December 2021 focused on these two challenges and developed recommendations for improved practices. Discussion The participants agreed that prioritization of measurands for standardization should be based on their impact on medical decisions in a clinical pathway. Ensuring that matrix-based CRMs are globally available for more measurands will enable fit-for-purpose calibration hierarchies for more laboratory tests. Regulation of laboratory tests is important to ensure safety and effectiveness for the populations served. Because regulations are country or region specific, manufacturers must submit recalibration changes intended to standardize results for regulatory review to all areas in which a measuring system is marketed. Recommendations A standardization initiative requires collaboration and planning among all interested stakeholders. Global collaboration should be further developed for prioritization of measurands for standardization, and for coordinating the production and supply of CRMs worldwide. More uniform regulatory submission requirements are desirable when recalibration is implemented to achieve internationally standardized results.

Objectives Quantitative protein mass-spectrometry (QPMS) in blood depends on tryptic digestion of proteins and subsequent measurement of representing peptides. Whether serum and plasma can be used interchangeably and whether in-vitro anticoagulants affect the recovery is unknown. In our laboratory serum samples are the preferred matrix for QPMS measurement of multiple apolipoproteins. In this study, we investigated the effect of different matrices on apolipoprotein quantification by mass spectrometry. Methods Blood samples were collected from 44 healthy donors in Beckton Dickinson blood tubes simultaneously for serum (with/without gel) and plasma (heparin, citrate or EDTA). Nine apolipoproteins were quantified according to standard operating procedure using value-assigned native serum calibrators for quantitation. Tryptic digestion kinetics were investigated in the different matrices by following formation of peptides for each apolipoprotein in time, up to 22 h. Results In citrate plasma recovery of apolipoproteins showed an overall reduction with a bias of −14.6%. For heparin plasma only −0.3% bias was found compared to serum, whereas for EDTA-plasma reduction was more pronounced (−5.3% bias) and variable with >14% reduction for peptides of apoA-I, A-II and C-III. Digestion kinetics revealed that especially slow forming peptides showed reduced formation in EDTA-plasma. Conclusions Plasma anticoagulants affect QPMS test results. Heparin plasma showed comparable results to serum. Reduced concentrations in citrate plasma can be explained by dilution, whereas reduced recovery in EDTA-plasma is dependent on altered proteolytic digestion efficiency. The results highlight the importance of a standardized pre-analytical phase for accurate QPMS applications in clinical chemistry.

Objectives Liquid chromatography-tandem mass spectrometry (LC-MS/MS) panels that include glucocorticoid-related steroids are increasingly used to characterize and diagnose adrenal cortical diseases. Limited information is currently available about reproducibility of these measurements among laboratories. The aim of the study was to compare LC-MS/MS measurements of corticosterone, 11-deoxycortisol and cortisone at eight European centers and assess the performance after unification of calibration. Methods Seventy-eight patient samples and commercial calibrators were measured twice by laboratory-specific procedures. Results were obtained according to in-house and external calibration. We evaluated intra-laboratory and inter-laboratory imprecision, regression and agreement against performance specifications derived from 11-deoxycortisol biological variation. Results Intra-laboratory CVs ranged between 3.3 and 7.7%, 3.3 and 11.8% and 2.7 and 12.8% for corticosterone, 11-deoxycortisol and cortisone, with 1, 4 and 3 laboratories often exceeding the maximum allowable imprecision (MAI), respectively. Median inter-laboratory CVs were 10.0, 10.7 and 6.2%, with 38.5, 50.7 and 2.6% cases exceeding the MAI for corticosterone, 11-deoxycortisol and cortisone, respectively. Median laboratory bias vs. all laboratory-medians ranged from −5.6 to 12.3% for corticosterone, −14.6 to 12.4% for 11-deoxycortisol and −4.0 to 6.5% for cortisone, with few cases exceeding the total allowable error. Modest deviations were found in regression equations among most laboratories. External calibration did not improve 11-deoxycortisol and worsened corticosterone and cortisone inter-laboratory comparability. Conclusions Method imprecision was variable. Inter-laboratory performance was reasonably good. However, cases with imprecision and total error above the acceptable limits were apparent for corticosterone and 11-deoxycortisol. Variability did not depend on calibration but apparently on imprecision, accuracy and specificity of individual methods. Tools for improving selectivity and accuracy are required to improve harmonization.

Objectives Vitamin D-binding protein (VDBP), a serum transport protein for 25-hydroxyvitamin D [25(OH)D], has three common proteoforms which have co-localized amino acid variations and glycosylation. A monoclonal immunoassay was found to differentially detect VDBP proteoforms and methods using liquid chromatography-tandem mass spectrometry (LC-MS/MS) might be able to overcome this limitation. Previously developed multiple reaction monitoring LC-MS/MS methods for total VDBP quantification represent an opportunity to probe the potential effects of proteoforms on proteolysis, instrument response and quantification accuracy. Methods VDBP was purified from homozygous human donors and quantified using proteolysis or acid hydrolysis and LC-MS/MS. An interlaboratory comparison was performed using pooled human plasma [Standard Reference Material ® 1950 (SRM 1950) Metabolites in Frozen Human Plasma] and analyses with different LC-MS/MS methods in two laboratories. Results Several shared peptides from purified proteoforms were found to give reproducible concentrations [≤2.7% coefficient of variation (CV)] and linear instrument responses (R 2 ≥0.9971) when added to human serum. Total VDBP concentrations from proteolysis or amino acid analysis (AAA) of purified proteoforms had ≤1.92% CV. SRM 1950, containing multiple proteoforms, quantified in two laboratories resulted in total VDBP concentrations with 7.05% CV. Conclusions VDBP proteoforms were not found to cause bias during quantification by LC-MS/MS, thus demonstrating that a family of proteins can be accurately quantified using shared peptides. A reference value was assigned for total VDBP in SRM 1950, which may be used to standardize methods and improve the accuracy of VDBP quantification in research and clinical samples.

Objectives Measurement of the serum levels of vitamin B12 (VB12) is key for evaluating VB12 deficiency-dependent anemia. Immunoassay, the major method for determining VB12, tends to give false-normal results because of the presence of anti-intrinsic factor (IF-Ab) or other factors such as heterophilic antibodies et al. This study aimed to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method that is helpful for distinguish false normal VB12 results measured by the immunoassay. Methods Different forms of VB12 were derivatized into CN-B12, which was collected through solid-phase extraction and analyzed via LC-MS/MS. 236 serum samples were measured both by LC-MS/MS and immunoassay, results were compared, and the IF-Ab effect was evaluated. Results The LC-MS/MS assay afforded a linear slope from 20 to 4,000 pmol/L for CN-B12. OH-VB12, methyl-VB12, and CoA-VB12 showed recovery within 89.3–109.5%. The intra-assay CV of VB12 was 2.6–4.1%, whereas the total CV was 9.3–9.8%. Passing–Bablok regression between LC-MS/MS and immunoassay results showed that the slope was 1.085 and the intercept was −15.691. The Bland–Altman plot showed that the mean difference and difference% were −34.6 pmol/L and 0.3%, respectively. Inter-rater agreement analysis showed that the linear weighted kappa value was 0.885, implying good agreement between the two methods. However, two samples were falsely elevated and one sample was falsely normal in the immunoassay compared with LC-MS/MS. The LC-MS/MS method helped in the distinction of false-normal VB12 results shown by the immunoassay. Conclusions The VB12 LC-MS/MS method can be used as an arbiter of clinically discordant immunoassay results.

Objectives Clinical decision-making in emergency medicine is under constant pressure from demand and performance requirements, with blood tests being a fundamental part of this. However, the preanalytical process has received little attention. Therefore, this study aimed to investigate the quality of preanalytical phase processes in European emergency departments (EDs) from the perspectives of the three main providers: clinicians, nurses, and laboratory specialists. Methods This online survey, distributed among European EDs and laboratories, was supported by the European Society for Emergency Nursing (EUSEN), European Society for Emergency Medicine (EuSEM), and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM). The size of the centres, the European region, the responder’s profession and the country’s economic condition were used as co-variables. Results We included 376 responses from all ED-related professions from 306 European centres. In 66.9% of all ED visits, at least one blood test was performed. Tests were requested mostly by nurses (44.6%) using electronic Order/Entry systems (65.4%). Only a minority (19%) reported not using laboratory quality indicators (QIs). Most responders defined the TAT starting point “when the laboratory receives the sample” (66.1%), defining the goal to be “less than 60 min” (69.9%), but only 42.4% of the centres estimated achieving this goal. Conclusions Our survey illustrates the current situation on preanalytical blood sample processing in European EDs from the clinical and laboratory perspectives. The results emphasise the importance of the IT infrastructure and QI usage in this process and highlight some differences between European regions.

Objectives Accurate determination of glomerular filtration rate (GFR) is important. Several endogenous biomarkers exist for estimating GFR, yet, they have limited accuracy, especially in the paediatric population. Proenkephalin A 119–159 (PENK) is a novel and promising GFR marker, but its relation with age in children remains unknown. Also, the value of PENK has never been validated against measured GFR (mGFR) in children when compared to traditional GFR markers including serum creatinine (SCr), SCr-based estimated GFR (eGFR) and cystatin C (cysC). Methods Critically ill children and term-born neonates were included in this single-centre, prospective study. Iohexol-based mGFR, SCr, and cysC were determined in each patient. eGFR was calculated using the bedside Schwartz equation, incorporating SCr and height. Spearman correlation coefficients were calculated to determine the correlation between mGFR and PENK, SCr, cysC and eGFR. Results For 97 patients (56 children and 41 neonates), mGFR, SCr, cysC and PENK levels were available. PENK levels were higher in young children and decreased to adult PENK reference values around two years of age. PENK levels were highly correlated with mGFR (ρ=−0.88, p<0.001), and similar to mGFR–eGFR correlation (ρ=−0.87, p<0.001). For cysC and SCr the correlation with mGFR was lower (ρ=−0.77 and ρ=−0.46, respectively. Both p<0.001). Conclusions The correlation of PENK with mGFR was as good as SCr-based eGFR-mGFR correlation. To determine the added value of PENK in paediatric clinical care and prior to implementation, PENK reference values are needed and the development and validation of a paediatric PENK-based eGFR equation is necessary.

Objectives Umbilical cord blood gases (UBG) may be a critical element in the assessment of a depressed newborn infant but in some cases the arterial or venous UBG source is uncertain making clinical and/or medical-legal interpretation difficult. Objective: to estimate the probability of an arterial (ProbAS) or venous (ProbVS) UBG source depending on blood gas parameters in acidemic cases. Methods A total of 56,703 pairs of concomitant arterial and venous (CAV) UBG results assayed over an 8.8-year period were analyzed. Specimen pairs with preanalytical issues, duplicate source, or physiologically out-of-range or uninterpretable results were excluded. The 3,579 CAV-UBGs with an arterial and venous pH 6.70 to 7.25 were analyzed. Generalized additive model (gam)-based binomial logistic regressions were used to determine the ProbAS and ProbVS according to the blood gas parameters. Results The relative differences between arterial and venous medians were: pO 2 ‒47%, pCO 2 22%, pH −11%, and BD 4%. Below a median of 2.4 kPa, the lower the pO 2 , the higher the ProbAS. Above this value, the higher the pO 2 , the lower the ProbAS. An Excel worksheet is provided to calculate ProbAS and ProbVS from the regression model for different combinations of pH, pCO 2 , and pO 2 values. Considering ProbAS and ProbVS above a cutoff 0.8, the model correctly identified the source in 56% of cases while 41% were indeterminant and 3% were erroneous. Conclusions The probability of an arterial or venous source of an umbilical blood gas can be estimated based on the pH, pCO 2 , and pO 2 in most acidemic specimens.

Objectives Clinical laboratory investigation of autoimmune, metabolic, and oncologic disorders in children and adolescents relies on appropriateness of reference intervals (RIs). The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) previously established comprehensive pediatric RIs for specialized immunoassays on the Abbott ARCHITECT system. Herein, we aim to verify performance on new Alinity i assays by evaluating sera collected from healthy children as per Clinical and Laboratory Standards Institute (CLSI) EP-28A3C guidelines. Methods Precision, linearity, and method comparison experiments were completed for 17 specialized Alinity immunoassays, including cancer antigens, autoimmune peptides, and hormones. Sera collected from healthy children and adolescents (birth-18 years, n=100) were evaluated. CLSI-based verification was completed using previously established CALIPER RIs for ARCHITECT assays as the reference. Results Of 17 specialized immunoassays assays, only anti-cyclic citrullinated peptides (anti-CCP) did not meet acceptable verification criterion (i.e., ≥90% of results within ARCHITECT reference CI). Anti-thyroglobulin, anti-thyroid peroxidase, and carcinoembryonic antigen did not require age-specific consideration beyond one year of age, with 63, 91, and 80% of samples equalling the limit of detection, respectively. Estimates were separated by sex for relevant assays (e.g., sex hormone binding globulin, total and free prostate specific antigen). Conclusions Findings support transferability of pediatric RIs on ARCHITECT system to the Alinity system for 16 specialized immunoassays in the CALIPER cohort and will be a useful resource for pediatric clinical laboratories using Alinity assays. Further work is needed to establish evidence-based interpretative recommendations for anti-CCP and continue to evaluate pediatric RI acceptability for newly available assay technologies.

Objectives CellaVision DC-1 (DC-1, Sysmex, Kobe, Japan) is a newly launched digital morphology analyzer that was developed mainly for small to medium-volume laboratories. We evaluated the precision, qualitative performance, comparison of cell counts between DC-1 and manual counting, and turnaround time (TAT) of DC-1. Methods Using five peripheral blood smear (PBS) slides spanning normal white blood cell (WBC) range, precision and qualitative performance of DC-1 were evaluated according to the Clinical and Laboratory Standards Institute (CLSI) EP15-A3, EP15-Ed3-IG1, and EP12-A2 guidelines. Cell counts of DC-1 and manual counting were compared according to the CLSI EP 09C-ED3 guidelines, and TAT of DC-1 was also compared with TAT of manual counting. Results DC-1 showed excellent precision (%CV, 0.0–3.5%), high specificity (98.9–100.0%), and high negative predictive value (98.4–100.0%) in 18 cell classes (12 WBC classes and six non-WBC classes). However, DC-1 showed 0% of positive predictive value in seven cell classes (metamyelocytes, myelocytes, promyelocytes, blasts, plasma cells, nucleated red blood cells, and unidentified). The largest absolute mean differences (%) of DC-1 vs. manual counting was 2.74. Total TAT (min:s) was comparable between DC-1 (8:55) and manual counting (8:55). Conclusions This is the first study that comprehensively evaluated the performance of DC-1 including its TAT. DC-1 has a reliable performance that can be used in small to medium-volume laboratories for assisting PBS review. However, DC-1 may make unnecessary workload for cell verification in some cell classes.

Objectives We assessed the inter-method bias of total (tPSA) and free (fPSA) prostate-specific antigen (PSA) immunoassays to establish if tPSA-based risk thresholds for advanced prostate cancer (PCa), obtained from one method (Roche) can be converted into the corresponding concentrations assayed by other methods. Then we evaluated the impact of the bias of tPSA and fPSA on the estimation of the %f/tPSA ratio and performed a re-calibration of the proposed thresholds for the %f/tPSA ratio according to the assay used. Methods tPSA and fPSA were measured in 135 and 137 serum samples, respectively by Abbott Alinity i, Beckman Access Dxl, Roche Cobas e801, and Siemens Atellica IM analytical platforms. Scatterplots, Bland-Altman diagrams, Passing-Bablok (PB) were used to inspect and estimate the systematic and proportional bias between the methods. The linear equations with confidence intervals of the parameter estimates were used to transform the tPSA risk thresholds for advanced PCa into the corresponding concentrations measurable by the other analytical methods. To construct a correction coefficient for converting the %f/tPSA ratio from one method to the other, PB and non-parametric boostrapping were used. Results The inter-method bias is not constant but strictly linear allowing the conversion of PSA results obtained from Roche into the other assays, which underestimate tPSA vs. Roche. Siemens and Abbott vs. Roche and Beckman assays, being characterized by a positive and a negative proportional bias for tPSA and fPSA measurements, tend to overestimate the %f/tPSA ratio. Conclusions There is a consistent risk to miss advanced PCa, if appropriate conversion factors are not applied.

Objectives Immune checkpoint inhibitors (ICIs) cause a variety of toxicities, including immune-related adverse events (irAEs), but there are no biomarkers to predict their development. Guidelines recommend measuring circulating cardiac troponin I (cTnI) during ICI therapy to detect related cardiotoxicities. Moreover, elevated cTnI has also been associated with worse outcomes in non-cardiac patients, including cancer. Thus here, we investigated whether cTnI levels were higher in patients with irAEs. Methods The study consisted of three groups; 21 cancer patients undergoing ICI immunotherapies who presented with irAEs, four patients without irAEs, and 20 healthy controls. Patient samples were assessed at baseline (n=25), during ICI treatment (n=25, median=6 weeks of treatment) and at toxicity (n=6, median=13 weeks of treatment). In addition to blood high sensitivity cardiac troponin I (hs-cTnI), anti-thyroglobulin (TG) and anti-thyroid peroxidase (TPO) antibodies were also quantitated to detect thyroid dysfunction, constituting the second leading toxicity (23.8%) after pneumonitis (28.6%). Results Four patients with irAEs (n=4/21; 19%) and one without irAEs (n=1/4; 25%) showed higher hs-cTnI levels at any time-point; the remaining had physiological levels. None of these patients developed cardiotoxicity. Concurrent elevated levels of anti-thyroid antibodies and hs-cTnI were detected in one patient with thyroid dysfunction (n=1/5, 20%). However, these antibodies were also elevated in three patients (n=3/16, 19%) with non-thyroid irAEs and in up to 40% of healthy controls. Conclusions hs-cTnI was not elevated in patients with irAEs, but larger studies are needed to confirm these observations.

Objectives This study aims to investigate whether combining scoring systems with monocyte distribution width (MDW) improves early sepsis detection in older adults in the emergency department (ED). Methods In this prospective observational study, we enrolled older adults aged ≥60 years who presented with confirmed infectious diseases to the ED. Three scoring systems—namely quick sepsis-related organ failure assessment (qSOFA), Modified Early Warning Score (MEWS), and National Early Warning Score (NEWS), and biomarkers including MDW, neutrophil-to-lymphocyte ratio (NLR), and C-reactive protein (CRP), were assessed in the ED. Logistic regression models were used to construct sepsis prediction models. Results After propensity score matching, we included 522 and 2088 patients with and without sepsis in our analysis from January 1, 2020, to September 30, 2021. NEWS ≥5 and MEWS ≥3 exhibited a moderate-to-high sensitivity and a low specificity for sepsis, whereas qSOFA score ≥2 demonstrated a low sensitivity and a high specificity. When combined with biomarkers, the NEWS-based, the MEWS-based, and the qSOFA-based models exhibited improved diagnostic accuracy for sepsis detection without CRP inclusion (c-statistics=0.842, 0.842, and 0.826, respectively). Of the three models, MEWS ≥3 with white blood cell (WBC) count ≥11 × 10 9 /L, NLR ≥8, and MDW ≥20 demonstrated the highest diagnostic accuracy in all age subgroups (c-statistics=0.886, 0.825, and 0.822 in patients aged 60–74, 75–89, and 90–109 years, respectively). Conclusions Our novel scoring system combining MEWS with WBC, NLR, and MDW effectively detected sepsis in older adults.

Objectives Since December 2019, the worldwide public health has been threatened by a severe acute respiratory syndrome caused by Coronavirus-2. From the beginning, a turning point has been the identification of new cases of infection, in order to minimize the virus spreading among the population. For this reason, it was necessary introducing a panel of tests able to identify positive cases, which became crucial for all countries. Methods As a Regional Reference Centre, the CRQ Laboratory (Regional Laboratory for the Quality Control) developed and conducted an External Quality Assessment (EQA) panel of assay, so as to evaluate the quality of real-time reverse transcription polymerase chain reaction (PCR), which were used by 62 Sicilian laboratories, previously authorized to issue certificates for the COVID-19 diagnosis, on behalf of the Public Health Service. Results The qualitative performance test was based on pooled samples with different viral loads of SARS-CoV-2 or human Coronavirus OC43. 75% of the participating laboratories tested all core samples correctly, while the remaining 25% interpreted incorrectly the EQA exercise samples matching negatively the standards required. Conclusions Subsequent inspection visits confirmed the issue of incorrect positive and negative certifications for COVID-19 by private and public laboratories, despite the possession of the authorization requirements currently provided for by current regulations, with a significant impact on the SSR.