Volume 60, Issue 8

Perinatal sepsis constitutes a medical emergency and is still one of the major causes of mortality and morbidity. The possibility of an early diagnosis of sepsis is still debated and controversial. In particular, clinical symptoms can be hidden by the association of sepsis with other perinatal diseases and/or by therapeutic strategies performed. In this context, there is evidence that the accuracy of standard of care diagnostic parameters (i.e. blood culture, C-reactive protein, procalcitonin) can be biased by additional confounding factors (gestational age, birth-weight, acute-chronic hypoxia). Therefore, the inclusion in clinical daily practice of new biomarkers of sepsis is of utmost importance. Of a panel of biomarkers, Presepsin (P-SEP) plays an important role in the development and response of the immune system and as an early marker of sepsis both in adult and pediatric patients. Therefore, in the present review we aim to offer an overview of the role of P-SEP in the early detection of perinatal sepsis as a trustworthy marker according to actual statements of official international institutions. Future perspectives regard the possibility of a longitudinal non-invasive biological fluids P-SEP assessment thus limiting the sample stress in high risk newborns.

Epidemiological and clinical studies show a causal association between serum triglyceride (TG) level, the number of triglyceride-rich lipoproteins (TRLs) and their remnants, and the increased risk of atherosclerosis and cardiovascular disease (CVD) development. In light of current guidelines for dyslipidemia management, the laboratory parameters reflecting TRL content are recommended as part of the routine lipid analysis process and used for CVD risk assessment, especially in people with hypertriglyceridemia (HTG), diabetes mellitus, obesity and low levels of low-density lipoprotein cholesterol (LDL-C), in which high residual CVD risk is observed. The basic routinely available laboratory parameters related with TRL are serum TG and non-high-density lipoprotein cholesterol (non-HDL-C) levels, but there are also other biomarkers related to TRL metabolism, the determination of which can be helpful in identifying the basis of HTG development or assessing CVD risk or can be the target of pharmacological intervention. In this review, we present the currently available laboratory parameters related to HTG. We summarise their link with TRL metabolism and HTG development, the determination methods as well as their clinical significance, the target values and interpretation of the results in relation to the current dyslipidemia guidelines.

Health technology assessment is a key tool for ensuring healthcare quality, accessibility, and sustainability. The novel European Union (EU) Health Technology Assessment (HTA) regulation of 15 December 2021, in harmonizing the laws of the Member States about the procedures and criteria for the evaluation of health technologies (i.e., medical devices and in vitro diagnostic tools), constitutes a significant achievement in the definition of EU health policies. On the one hand, for the European Union, it constitutes an essential driving force for the development of a competitive market for health technologies and, on the other, for European citizens, it guarantees the application of superordinate safety and quality standards with an impact positive on access to health technologies, including expressly also in vitro diagnostic medical devices classified in class D by art. 47 of Reg. (EU) 2017/746. As pointed out by the European Commissioner for Healthcare, the regulation identifies a new way for the Member States to cooperate on healthcare matters in the Union. The clinical efficacy and safety of drugs and devices are legal assets that today find their protection in a binding and directly applicable regulatory instrument, superordinate in the hierarchy of sources. Implementing the regulation will also be essential to achieve the objectives of the Union’s pharmaceutical strategy and the European plan to fight cancer. The novel HTA European regulation, applicable from January 2025, will ensure inclusion and transparency in evaluating health technologies and increase the predictability of decisions for both Member State authorities and industry.

Objectives One approach to assessing reference material (RM) commutability and agreement with clinical samples (CS) is to use ordinary least squares or Deming regression with prediction intervals. This approach assumes constant variance that may not be fulfilled by the measurement procedures. Flexible regression frameworks which relax this assumption, such as quantile regression or generalized additive models for location, scale, and shape (GAMLSS), have recently been implemented, which can model the changing variance with measurand concentration. Methods We simulated four imprecision profiles, ranging from simple constant variance to complex mixtures of constant and proportional variance, and examined the effects on commutability assessment outcomes with above four regression frameworks and varying the number of CS, data transformations and RM location relative to CS concentration. Regression framework performance was determined by the proportion of false rejections of commutability from prediction intervals or centiles across relative RM concentrations and was compared with the expected nominal probability coverage. Results In simple variance profiles (constant or proportional variance), Deming regression, without or with logarithmic transformation respectively, is the most efficient approach. In mixed variance profiles, GAMLSS with smoothing techniques are more appropriate, with consideration given to increasing the number of CS and the relative location of RM. In the case where analytical coefficients of variation profiles are U-shaped, even the more flexible regression frameworks may not be entirely suitable. Conclusions In commutability assessments, variance profiles of measurement procedures and location of RM in respect to clinical sample concentration significantly influence the false rejection rate of commutability.

Objectives Detection of between-lot reagent bias is clinically important and can be assessed by application of regression-based statistics on several paired measurements obtained from the existing and new candidate lot. Here, the bias detection capability of six regression-based lot-to-lot reagent verification assessments, including an extension of the Bland–Altman with regression approach are compared. Methods Least squares and Deming regression (in both weighted and unweighted forms), confidence ellipses and Bland–Altman with regression (BA-R) approaches were investigated. The numerical simulation included permutations of the following parameters: differing result range ratios (upper:lower measurement limits), levels of significance (alpha), constant and proportional biases, analytical coefficients of variation (CV), and numbers of replicates and sample sizes. The sample concentrations simulated were drawn from a uniformly distributed concentration range. Results At a low range ratio (1:10, CV 3%), the BA-R performed the best, albeit with a higher false rejection rate and closely followed by weighted regression approaches. At larger range ratios (1:1,000, CV 3%), the BA-R performed poorly and weighted regression approaches performed the best. At higher assay imprecision (CV 10%), all six approaches performed poorly with bias detection rates <50%. A lower alpha reduced the false rejection rate, while greater sample numbers and replicates improved bias detection. Conclusions When performing reagent lot verification, laboratories need to finely balance the false rejection rate (selecting an appropriate alpha) with the power of bias detection (appropriate statistical approach to match assay performance characteristics) and operational considerations (number of clinical samples and replicates, not having alternate reagent lot).

Objectives Proposal of a risk analysis model to diminish negative impact on patient care by preanalytical errors in blood gas analysis (BGA). Methods Here we designed a Failure Mode and Effects Analysis (FMEA) risk assessment template for BGA, based on literature references and expertise of an international team of laboratory and clinical health care professionals. Results The FMEA identifies pre-analytical process steps, errors that may occur whilst performing BGA (potential failure mode), possible consequences (potential failure effect) and preventive/corrective actions (current controls). Probability of failure occurrence (OCC), severity of failure (SEV) and probability of failure detection (DET) are scored per potential failure mode. OCC and DET depend on test setting and patient population e.g., they differ in primary community health centres as compared to secondary community hospitals and third line university or specialized hospitals. OCC and DET also differ between stand-alone and networked instruments, manual and automated patient identification, and whether results are automatically transmitted to the patient’s electronic health record. The risk priority number (RPN = SEV × OCC × DET) can be applied to determine the sequence in which risks are addressed. RPN can be recalculated after implementing changes to decrease OCC and/or increase DET. Key performance indicators are also proposed to evaluate changes. Conclusions This FMEA model will help health care professionals manage and minimize the risk of preanalytical errors in BGA.

Objectives A carrier prototype by Aerocom ® (Schwäbisch Gmünd, Germany) for pneumatic tube systems (PTS) is able to transport 9 blood tubes which are automatically fixed by closing the lid. In this study, we examined the influence of the transport on blood sample quality using the carrier prototype comparing to courier transport and a conventional carrier (AD160, Aerocom ® ). Methods Triplicate blood samples sets (1 lithium heparin, 1 EDTA, 1 sodium citrate) of 35 probands were split among the transportation methods: 1. courier, 2. conventional carrier, and 3. carrier prototype. After transport 51 measurands from clinical chemistry, hematology and coagulation were measured and compared. Results Overall, 49 of the investigated 51 measurands showed a good concordance among the three transport types, especially between the conventional carrier and the carrier prototype. Focusing on well-known hemolysis sensitive measurands, potassium showed no statistically significant differences. However, between courier and both carrier types lactate dehydrogenase (LDH) and free hemoglobin (fHb) showed statistically significant shifts, whereas the clinical impact of the identified differences was neglectable. The median concentration of fHb, for example, was 0.29 g/L (18 µmol/L), 0.31 g/L (19 µmol/L) and 0.32 g/L (20 µmol/L) for courier transport, conventional carrier and carrier prototype, respectively. These differences cannot be resolved analytically since the minimal difference (MD) for fHb is 0.052 g/L (3.23 µmol/L), at this concentration. Conclusions The carrier prototype by Aerocom ® is suitable for transportation of diagnostic blood samples. The overall workflow is improved by decreasing hands-on-time on the ward and laboratory while minimizing the risk of incorrectly packed carriers.

Objectives Fast and reliable ethanol assays analysis are used in a clinical context for patients suspected of ethanol intoxication. Mostly, automated systems using an enzymatic reaction based on ethanol dehydrogenase are used. The manuscript focusses on the evaluation of the performance of these assays. Methods Data included 30 serum samples used in the Belgian EQA scheme from 2019 to 2021 and concentrations ranged from 0.13 to 3.70 g/L. A regression line between target concentrations and reported values was calculated to evaluate outliers, bias, variability and measurement uncertainty. Results A total of 1,611 results were taken into account. Bias was the highest for Alinity c over the whole concentration range and the lowest for Vitros for low concentrations and Cobas 8000 using the c702 module for high concentrations. The Architect and Cobas c501/c502 systems showed the lowest variability over the whole concentration range. Highest variability was observed for Cobas 8000 using the 702 module, Thermo Scientific and Alinity c. Cobas 8000 using the c702 module showed the highest measurement uncertainty for lower concentrations. For higher concentrations, Alinity c, Thermo Scientific and Vitros were the methods with the highest measurement uncertainty. Conclusions The bias of the enzymatic techniques is nearly negligible for all methods except Alinity c. Variability differs strongly between measurement procedures. This study shows that the Alinity c has a worse measurement uncertainty than other systems for concentrations above 0.5 g/L. Overall, we found the differences in measurement uncertainty to be mainly influenced by the differences in variability.

Objectives Living kidney donors provide a unique setting to study functional and metabolic consequences after organ donation. Since the lack of data of the homoeostasis of numerous vitamin D metabolites in these healthy subjects, the aim of this study was to assess the vitamin D metabolism before and after kidney donation. Methods We investigated the 25-dihydroxyvitamin D 2 (25[OH]D 2 ), 25-dihydroxyvitamin D 3 (25[OH]D 3 ), 1,25-dihydroxyvitamin D 3 (1,25[OH] 2 D 3 ), 24,25-dihydroxyvitamin D 3 (24,25[OH] 2 D 3 ), 25,26-dihydroxyvitamin D 3 (25,26[OH] 2 D 3 ), and the native vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) in a well characterized study cohort of 32 healthy living kidney donors before and after organ donation. Results Thirty-two healthy subjects after kidney donation had significantly lower median (interquartile range) 1,25(OH) 2 D 3 serum concentrations (88.6 [62.6–118.8] vs. 138.0 [102.6–152.4] pmol/L, p<0.001) and significantly higher median 25(OH)D 2 serum levels (1.80 [1.19–2.19] vs. 1.11 [0.74–1.59] nmol/L, p=0.019) than before donation. Similar serum concentrations of 25(OH)D 3 and 25,26(OH) 2 D 3 were observed before and after donation. The 24,25(OH) 2 D 3 blood levels distinctly decreased after organ donation (4.1 [2.3–5.3] vs. 5.3 [2.2–6.9] nmol/L, p=0.153). Native vitamin D2 (0.10 [0.08–0.14] vs. 0.08 [0.06–0.12] nmol/L, p=0.275) was slightly increased and vitamin D3 (1.6 [0.6–7.2] vs. 2.5 [0.9–8.6] nmol/L, p=0.957) decreased after kidney donation. Conclusions Living kidney donors were found with decreased 1,25(OH) 2 D 3 and 24,25(OH) 2 D 3 , increased 25(OH)D 2 and consistent 25(OH)D 3 and 25,26(OH) 2 D 3 serum concentrations after organ donation. The current study advances the understanding on vitamin D metabolism suggesting that altered hydroxylase-activities after donation is accompanied by compensatory elevated dietary-related 25(OH)D 2 blood concentrations.

Objectives The 5α-reductase-type-2 deficiency (5ARD2) is a rare autosomal recessive 46,XY disorder of sex development caused by the mutated 5α-reductase type 2 ( SRD5A2 ) gene. In this disease, defective conversion of testosterone to dihydrotestosterone leads to variable presentations of male ambiguous genitalia during fetal development. We aimed to examine characteristics of patients presenting with 5ARD2 over a 4 year period. Methods Random urine samples of control and patients with suspected 5ARD2 were collected and urine steroidomic metabolites were measured by Gas chromatography-mass spectrometry (GC-MS) in the period from 2017 to 2021 at National Children’s Hospital, Hanoi Vietnam. 5α- to 5β-reduced steroid metabolite ratio, 5a-tetrahydrocortisol to tetrahydrocortisol (5α-THF/THF), was reviewed by receive operator characteristics (ROC) curve analysis. Molecular testing was offered to 25 patients who were diagnosed with 5ARD2 by GC-MS urinary steroid analysis. Results Urine steroidomic profiling was conducted for 104 male controls and 25 patients between the ages of 6 months and 13 years old. Twelve of the twenty-five 5ARD2 patients agreed to undertake genetic analysis, and two mutations of the SRD5A2 gene were detected in each patient, confirming the diagnosis. All patients showed a characteristically low ratio of 5α-THF/THF. There was no overlap of 5α-THF/THF ratio values between control and 5ARD2 groups. The ROC of 5α-THF/THF ratio at 0.19 showed 100% sensitivity and 100% specificity for boys between 6 months and 13 years of age. Conclusions Analysis of the urine steroid metabolome by GC-MS can be used to assist in the diagnosis of 5ARD2. We recommend consideration of random urine steroid analysis as a first-line test in the diagnosis of 5ARD2.

Objectives Serum S100B allows a one-third reduction of computed tomography (CT) scans performed for mild traumatic brain injury (mTBI) patients. In this study, we evaluated the diagnostic performance of serum NF-L in the detection of intracranial lesions induced by mTBI. Methods One hundred seventy-nine adult mTBI patients presenting to the emergency department of Clermont-Ferrand University Hospital with a Glasgow Coma Scale (GCS) score of 14–15 were included. S100B assays were performed for clinical routine while NF-L samples were stored at −80 °C until analysis. CT scans were performed for patients with S100B levels above the decision threshold of 0.10 μg/L. Later, NF-L and S100B levels were compared to CT scan findings to evaluate the biomarkers’ performances. Results The area under the ROC curve (AUC) evaluating the diagnostic ability in the prediction of intracranial lesions was 0.72 (95% CI; 0.58–0.87) for S100B and 0.58 (95% CI; 0.45–0.71) for NF-L, the specificities (at a threshold allowing a 100% sensitivity) were 35.7% for S100B, and 28% for NF-L (p=0.096). AUCs of NF-L and S100B for the identification of patients with neurological disorders were statistically different (p<0.001). The AUCs were 0.87 (95% CI; 0.82–0.93) for NF-L and 0.57 (95% CI; 0.48–0.66) for S100B. There was a poor correlation between NF-L and S100B, and NF-L levels were correlated to patients’ age (Spearman coefficient of 0.79). Conclusions NF-L showed poor performances in the early management of mTBI patients. NF-L levels are strongly correlated to neurodegeneration, whether physiological, age-related, or pathological.

Objectives Evaluation of the simultaneous measurement of urinary γ-glutamyltransferase (γGT) and lactate dehydrogenase (LDH) to discriminate fresh from previously frozen specimens in urine drug monitoring. Methods Two widely available photometric tests (Siemens Healthineers Atellica) were used to determine the range of urinary γGT and LDH excretion and to study the decay in urinary enzyme activity under various storage conditions (room temperature, 4–8 °C, −18 °C, −80 °C). From these data, cut-off values were established and evaluated in split (fresh/frozen) specimens. Results Both assays allow robust, reliable, and simultaneous determination of urinary γGT and LDH. In healthy subjects, the 95% reference intervals for enzyme activity in native urine were γGT: 24.4–100.4 U/g Crea (creatinine) and LDH: 2.5–45.8 U/g Crea. Frozen storage for at least 7 days at −18 °C resulted in a loss of activity to less than 50% in both enzymes. Cut-offs for frozen samples were γGT≤33.2 U/g Crea and LDH≤ 8.4 U/g Crea. When applied to 100 sample pairs (fresh/frozen), 86.5% (173/200) of the measurements were conclusive and the combination of concordant enzyme measurements (low γGT/low LDH or high γGT/high LDH) was able to predict the mode of storage with a sensitivity of 96.3% and a specificity of 96.7%. Conclusions The additional measurements of urinary γGT and LDH can be used to detect previously frozen urine specimens. A simple protocol is proposed to provide additional information on sample quality when deceit is suspected. The procedure can be easily integrated into the standard workflow of urinary drug monitoring.

Objectives Pediatric Reference Intervals in China (PRINCE) is a nationwide initiative that aims to establish and validate harmonized reference intervals (RIs) for Chinese children and adolescents, in which 15,150 healthy volunteers aged up to 20 years were recruited from 11 centers to establish RIs and 7,557 children and adolescents were enrolled from 21 centers to validate RIs. Methods The complete blood cell counts (CBC) of venous whole blood were measured by hematology analyzers through Sysmex systems in different centers. Age- and sex-specific RIs were calculated according to the guidelines. Results Unlike adults with certain levels of analyte concentrations, hematological parameters of children changed through growth and development. Red blood cell counts, hemoglobin, and hematocrit increased with age, and revealed higher concentrations in boys than girls after puberty. White blood cell counts and platelet counts showed significant higher levels than adults before 2 years of age, and then gradually decreased without distinct sex differences. In addition, lymphocyte counts decreased with age while neutrophil counts showed an opposite trend. The lower and upper limits of pediatric RIs of CBC were different from those of adults. Conclusions The validation of RIs indicated that the PRINCE study provided a version of RIs suitable for most of regions in China. This first harmonized pediatric RIs of CBC across China provided a robust database to understand the dynamic changes of hematologic parameters from birth to adolescence, and will contribute to clinical diagnosis and prognosis evaluation for pediatric patients as well.

Objectives Prostate cancer (PCa) represents the second most common solid cancer in men worldwide. In the last decades, the prostate health index (PHI) emerged as a reliable biomarker for detecting PCa and differentiating between non-aggressive and aggressive forms. However, before introducing it in clinical practice, more evidence is required. Thus, we performed a systematic review and meta-analysis for assessing the diagnostic performance of PHI for PCa and for detecting clinically significant PCa (csPCa). Methods Relevant publications were identified by a systematic literature search on PubMed and Web of Science from inception to January 11, 2022. Results Sixty studies, including 14,255 individuals, met the inclusion criteria for our meta-analysis. The pooled sensitivity and specificity of PHI for PCa detection was 0.791 (95%CI 0.739–0.834) and 0.625 (95%CI 0.560–0.686), respectively. The pooled sensitivity and specificity of PHI for csPCa detection was 0.874 (95%CI 0.803–0.923) and 0.569 (95%CI 0.458–0.674), respectively. Additionally, the diagnostic odds ratio was 6.302 and 9.206, respectively, for PCa and csPCa detection, suggesting moderate to good effectiveness of PHI as a diagnostic test. Conclusions PHI has a high accuracy for detecting PCa and discriminating between aggressive and non-aggressive PCa. Thus, it could be useful as a biomarker in predicting patients harbouring more aggressive cancer and guiding biopsy decisions.

Objectives Faecal immunochemical tests for haemoglobin (FIT) are used in colorectal cancer (CRC) screening programmes and to triage patients presenting with symptoms suggestive of CRC for further bowel investigations. There are a number of quantitative FIT analytical systems available. Currently, there is no harmonisation or standardisation of FIT methods. The aim of the study was to assess the comparability of numerical faecal haemoglobin concentrations (f-Hb) obtained with four quantitative FIT systems and the diagnostic accuracy at different f-Hb thresholds. Methods A subgroup of the National Institute for Health and Care Excellence (NICE) FIT study, a multicentre, prospective diagnostic accuracy study were sent four FIT specimen collection devices from four different FIT systems or two FIT devices for one FIT system. Faecal samples were examined and analysis of results carried out to assess difference between methods at thresholds of limit of detection (LoD), 10 µg haemoglobin/g faeces (µg/g) and 100 μg/g. Results 233 patients returned specimen collection devices for examination on four different systems; 189 patients returned two FIT kits for one system. At a threshold of 100 μg/g the sensitivity is the same for all methods. At lower thresholds of LoD and 10 μg/g differences were observed between systems in terms of patients who would be referred and diagnostic accuracies. Conclusions The lack of standardisation or harmonisation of FIT means that differences are observed in f-Hb generated on different systems. Further work is required to understand the clinical impact of these differences and to minimise them.

Objectives Circulating DNA (cirDNA) is generally purified from plasma that has been biobanked for variable lengths of time. In long-term experiments or clinical trials, the plasma can be stored frozen for up to several years. Therefore, it is crucial to determine the stability of cirDNA to ensure confidence in sample quality upon analysis. Our main objective was to determine the effect of storage for up to 2 years on cirDNA yield and fragmentation. Methods We stored frozen EDTA plasma and purified cirDNA from 10 healthy female donors, then quantified cirDNA yield at baseline, and at regular intervals for up to 2 years, by qPCR and Qubit. We also compared cirDNA levels in non-haemolysed and haemolysed blood samples after 16 months of storage and tested the effect of varying DNA extraction protocol parameters. Results Storage up to two years caused an annual cirDNA yield decline of 25.5% when stored as plasma and 23% when stored as purified DNA, with short fragments lost more rapidly than long fragments. Additionally, cirDNA yield was impacted by plasma input and cirDNA elution volumes, but not by haemolysis. Conclusions The design of long-term cirDNA-based studies and clinical trials should factor in the deterioration of cirDNA during storage.

Objectives To validate the analytical performance and diagnostic accuracy for non-ST-segment elevation myocardial infarction (NSTEMI) with a new high-sensitivity cardiac troponin I (hs-cTnI) assay on the automated light-initiated chemiluminescent assay (LiCA ® ) platform. Methods Comprehensive analytical validations were performed, and the 99th percentile upper reference limit (URL) from apparently healthy individuals were established. We evaluated the diagnostic performance of the assay for NSTEMI. Results The limit of quantitation (LoQ) were 1.9 ng/L (20% CV) and 5.1 ng/L (10% CV). The sex-specific 99th percentile URLs were 17.6 ng/L (4.2% CV) for men (age 20–79y) and 14.2 ng/L (4.9% CV) for women (age 19–89y) in serum, 14.4 ng/L (4.9% CV) for men (age 19–88y) and 12.9 ng/L (5.2% CV) for women (age 19–87y) in plasma, respectively. Detection rates in healthy individuals were from 98.7 to 99.1%. The correlation coefficient and median bias between LiCA and Architect were 0.985 and 0.1% (−2.0–2.9%) in full analytical range of serum specimens. In lower range (<100 ng/L), LiCA had an overall positive bias 6.7% (−1.6–13.3%), R=0.949. At the specific medical decision levels (15.2, 26.2 and 64.0 ng/L), assay difference was estimated to be <10%. No significant differences on AUC, sensitivity and specificity, NPV and PPV were found between LiCA and Architect for the diagnosis of NSTEMI. Conclusions LiCA hs-cTnI is a precise, highly sensitive and specific assay that meets the requirement of a 3rd generation (level 4) high-sensitivity method. The diagnostic accuracy of LiCA assay for NSTEMI is comparable to the established Architect hs-cTnI assay.

Objectives Results of earlier external quality assessment (EQA) rounds suggested remarkable differences in the sensitivity of SARS-CoV PCR assays. Although the test systems are intended to detect SARS-CoV-2 in individual samples, screening is often applied to sample pools to increase efficiency and decrease costs. However, it is unknown to what extent these tests actually meet the manufacturer’s specifications for sensitivity and how they perform when testing sample pools. Methods The sensitivity of assays in routine use was evaluated with a panel of positive samples in a round of a SARS-CoV-2 virus genome detection EQA scheme. The panel consisted of samples at or near the lower limit of detection (“weakly positive”). Laboratories that routinely test sample pools were asked to also analyze the pooled EQA samples according to their usual pool size and dilution method. Results All participants could detect a highly positive patient-derived sample (>10 6 copies/mL). Most (96%) of the test systems could detect at least 1,000 copies/mL, meeting the minimum acceptable benchmark, and many (94%) detected the vRNA in a sample with lower concentration (500 copies/mL). The false negative ratio increased to 16 and 26% for samples with 100 and 50 copies/mL, respectively. Conclusions The performance of most assays met or exceeded their specification on sensitivity. If assays are to be used to analyze sample pools, the sensitivity of the assay and the number of pooled samples must be balanced.