bluuebunny/crossref_metadata_2025 huggingface dataset:
A-005 Comparison of Performance of High Sensitive Troponin I (cTNIH) by “Point of care” (POC) and Automated cTNIH Immunoassays in Patients at Low Risk of Heart Attack in a Chilean Emergency Unit; Impact on E.R Department Efficiency
Authors: Ozaki B C , Mix A , Vivanco P
Published: October 2024

Background

Most cases of death from Acute Myocardial Infarction (AMI) occur in the first hours after the manifestation of clinical symptoms, constituting 40 to 65% in the first hour and approximately 80% in the first 24 hours. For the safe, effective, and rapid diagnosis of a patient with suspected AMI, international guidelines recommend that it be done based on clinical symptoms, together with electrocardiogram and analysis of biomarkers in the context of suspected of non-ST-elevation myocardial infarction (NSTEMI). Troponins are the biomarkers of choice with level A level evidence and the ability to perform screening in patients complaining of chest pain and refer it to the correct clinical approach based on the 0h/1h algorithm. To date, the successful clinical implementation of these rapid algorithms is restricted to hospitals working with well-defined workflows and a robust central laboratory structure. The Atellica® vTLi analyzer is based on the chemiluminescence methodology for the quantification of hs-cTnI levels with low sample volume, low complexity, and may enable the rapid management of patients with chest pain and application of 0h/1h algorithm.

Objectives

The aim of the study is to evaluate clinical performance in effectiveness and efficiency of the hs-cTnI Atellica® vTLi point of care test to rule out acute myocardial infarction in subjects with low-risk chest pain established with a validated predictive rule, in an adult-Chilean emergency unit, compared to clinical evaluation and the commonly used ADVIA Centaur® troponin test.

Methods

Descriptive, observational, longitudinal study. Patients over 18 years of age, consulting with acute chest pain of at least one hour from symptom onset and a HEART SCORE less than or equal to 3 points were recruited. A venous blood sample was requested for hs-cTnI analysis by Atellica® vTLi Siemens Healthineers and ADVIA Centaur® Siemens Healthineers. The time difference between sample collection and start of sample analysis; the time difference between sample collection and release of sample results was recorded and the concordance between the two results was determined.

Results

50 subjects were included in the study. The difference between blood sampling and start of sample analysis was 5 minutes with Atellica® vTLi POC and 68 minutes with ADVIA Centaur®. The concordance of hs-cTnI Atellica® vTLi POC and ADVIA Centaur® was 94% for predicting medical discharge and confirmed acute myocardial infarction.

Conclusions

The study findings support the safety and efficiency of the hs-cTnI POC test by providing faster results than central laboratory tests with the same analytical quality, with direct impact on reducing care times in patients consulting for low-risk chest pain.
A-011 Single High-Sensitivity Cardiac Troponin I Compared to High-Sensitivity Cardiac Troponin T Measurement to Rule Out Acute Myocardial Infarction at Low Risk for 30-Day Adverse Events: CONTRAST Study
Authors: Apple F S , Schulz K , Sandoval Y , Smith S , Carlson M , Kohl L , Rischall M , Gelin A , Wagner B , Gray R , Sexter A
Published: October 2024

Background

Cardiac troponin (cTn) is the preferred biomarker for diagnosing myocardial injury and acute myocardial infarction (MI). There are few comparative studies addressing the clinical performance of high-sensitivity (hs)-cTnI and hs-cTnT assays using fresh plasma for early rule out of myocardial infarction (MI) on presentation in patients presenting to emergency departments (ED). This study examined the performance strategies of a derived optimal concentration for a single high-sensitivity cardiac troponin I (hs-cTnI) measurement compared to a derived optimal concentration for a single high-sensitivity cardiac troponin T (hs-cTnT) measurement to rule out acute MI.

Methods

The COmparisoN of high-sensitivity cardiac TRoponin I and T ASsays Trial (CONTRAST) (NCT03214029) is a prospective, observational cohort study of consecutive adult ED patients (n = 2208) undergoing serial cTn measurements as clinically indicated. hs-cTnI (Abbott ARCHITECT) and hs-cTnT (Gen 5, Roche e601) measurements using fresh EDTA plasma were obtained. We determine optimal hs-cTn cutoffs for negative predictive value (NPV) and sensitivity for the diagnosis of acute MI (type 1 and type 2) to allow for a maximum number for early discharges with minimal risk of adverse events (acute MI or cardiac death) at 30 days.

Results

Acute MI occurred in 161 patients (7.3%), including 68 (42.2%) type 1 MI and 93 (57.7%) type 2 MI. For hs-cTnI (<2 ng/L) optimal NPV and sensitivity for adverse events were 99.1% (95% confidence interval 97.7%-99.8%) and 98.2% (CI. 95.4-99.5%). 450 Patients (21%) qualified for early rule out, at a 1.8% miss rate at 30 days. For hs-cTnT (<6 ng/L) optimal NPV and sensitivity for adverse events were 99.2% (CI 98.0%-99.8%) and 98.1% (CI. 95.3-99.5%). 513 Patients (24%) qualified for early rule out, at a 1.9% miss rate at 30 days.

Conclusions

In CONTRAST, a strategy using a single sample hs-cTnI or hs-cTnT alone allows for the early identification of patients unlikely to have acute MI and who are at very low risk for adverse events at 30 days. Minor differences existed between the Abbott ARCHITECT hs-cTnI assay and the Roche e601 hs-cTnT (Gen 5) assay in fresh plasma were found.
A-012 Predictive Value of Baseline Alpha Defensin Level in Patients with Stable Coronary Artery Disease: A Retrospective Single Center Study
Authors: Shapira M , Roguin A , Kobo O , Egbaria D , Amsalem N , Abu Fanne R
Published: October 2024

Background

Inflammation plays a central role in atherogenesis. The major neutrophilic peptide alpha-defensin is a promising evolving risk factor for atherosclerosis. The aim of the present study was to examine the role of alpha-defensin in predicting future major adverse cardiovascular events (MACE) occurrence in fully revascularized patients with stable coronary artery disease (CAD) under optimal medical therapy.

Methods

We retrospectively examined the prognostic value of baseline plasma alpha-defensin levels in predicting MACE occurrence in 174 fully revascularized patients for stable CAD. Demographic, clinical, angiographic, and laboratory data were collected from patients' electronic medical records (EMR). Alpha-defensin levels were measured in samples of EDTA plasma using ELISA kit (HyCult Biotechnology). Other Biochemical parameters were analyzed in serum using COBAS-8000 systems (Roche).

Results

Alpha-defensin levels were 20% higher among demised patients (10,859 pg/ml, IQR [6,920 to 23,320] vs. 9,020 pg/ml, IQR [5,540 to 16,180] pg/ml, P = 0.15). The absolute increase in mortality risk in patients with alpha-defensin levels greater than the median values was 72.5% (P = 0.33). Log-rank analysis proved both recurrent PCI for de novo lesions (14.9% and 2.3%) and the composite of mortality and recurrent PCI for de novo lesions (27.6% vs. 9.2%) were significantly related to alpha-defensin values greater than the median (>9200 pg/ml).

Conclusions

Baseline plasma alpha-defensin is an independent predictor of mortality and recurrent PCI among patients with stable CAD. Alpha-defensin may evolve as a promising factor in cardiovascular risk assessment beyond traditional risk factors. Targeting alpha-defensin to ameliorate MACE occurrence should be addressed in future studies.
A-018 Diagnostic Performance of the Novel Beckman-Coulter NT-proBNP-assay in the Early Diagnosis of Acute Heart Failure
Authors: Hammerer-Lercher A , Maria B , Wussler D , Lopez-Ayala P , Strebel I , Kozhuharov N , Sabti Z , Shrestha S , Prepoudis A , Schäfer I , Mork C , Wildi K , du Fay de Lavallaz J , Koechlin L , Zimmermann T , Nestelberger T , Boeddinghaus J , Breithardt T , Mueller C
Published: October 2024

Background

The diagnostic performance of the novel Beckman Coulter N-terminal pro-B-type natriuretic peptide (NT-proBNP) assay in the early diagnosis of acute heart failure (AHF) is unknown.

Methods

This major unmet clinical need was addressed in a secondary analysis using frozen plasma samples obtained in a prospective diagnostic study, enrolling patients presenting with acute dyspnea to the emergency department (ED). Two independent cardiologists/internists centrally adjudicated the final diagnosis using all individual patient's information. NT-proBNP-Beckman Coulter plasma concentrations were measured blinded and directly compared to NT-proBNP-Elecsys concentrations. Agreement analysis was performed by Bland Altman plot. The primary endpoints were the diagnostic accuracy of both assays using the Area-under-the-Receiver-Operating-Curve and the comparison of the performance for diagnosing AHF using the validated NT-proBNP-Elecsys clinical decision values (<300ng/L for rule-out, age-adjusted >450/900/1800ng/L for rule-in). The secondary endpoint included the application of the recently suggested NT-proBNP-Elecsys clinical decision values for obese patients.

Results

1400 patients (46% 3women, median age 76 years, BMI 25.9m2/kg, LVEF 53%) had both NT-proBNP measurements on presentation to the ED. Of those 744 (53%) had an adjudicated diagnosis of AHF. The agreement analysis showed overall higher concentrations for the NT-proBNP-Beckman assay. The diagnostic accuracy of both assays was excellent (AUC: 0.915 vs 0.922; P = 0.006, respectively). In the clinical application less patients were ruled-out using the Beckman assay compared to the Elecsys assay (18.7% vs 26.3%) with comparable sensitivities (98.9% vs 98.5%). Regarding rule-in NT-proBNP-Elecsys had a significantly higher specificity (78.8% vs 70.9%) and positive predictive value (83.1% vs 78.7%; both P<0.001; Figure 1). Similar findings were obtained in recently suggested cutoffs for obese patients.

Conclusions

In comparison to established NT-proBNP-Elecsys cutoffs, a derivation of Beckman-specific cutoffs is needed to implement NT-proBNP-Beckman Coulter clinical decision values providing a higher rule-out proportion and an optimal specificity for diagnosing AHF.
A-032 Accuracy of Immunoassay Testosterone Assays in Low Testosterone Patients
Authors: Deebajah M , Patel S , Keating M , Palmer O , Wheeler S E
Published: October 2024

Background

The measurement of testosterone in patients expected to have low testosterone levels can present a challenge to the clinical laboratory for turn-around-time and cost. At our institution send-out for measurement by mass spectrometry (MS) is the current standard in patients for whom we expect low testosterone levels. We aimed to investigate the utility of three immunoassay methodologies as a first line screen for testosterone levels by comparing results to mass spectrometry with an emphasis on specimens with low testosterone levels.

Methods

48 remnant plasma samples each from healthy men and women were aliquoted and stored at -80°C within 24 hours of draw (n=96 total specimens). Samples are remnants from out-patients being drawn for lipid profiles or other tests indicative of an annual wellness visit. Immunoassays were performed at the University of Pittsburgh Medical Center within the CAP accredited clinical laboratories. This study was approved by the University of Pittsburgh Institutional Review Board. The assays assessed were Access® Testosterone, Beckman Coulter (B-TST); Elecsys® Testosterone II, Roche Diagnostics (R-TST); Atellica® IM Testosterone II, Siemens Healthineers (S-TST). MS was sent to ARUP for testosterone analysis. The CDC Hormone Standardization program (HoSt) provides information of the accuracy of testosterone assays for participants. Both the S-TST and ARUP MS assays participate in this program.

Results

Results by MS ranged from 0.07 to 27.31 nmol/L. Correlation between testosterone by MS and immunoassays was strong with R2 >0.95 for all methods (B-TST: R2= 0.9570, y= 0.8588x + 0.9431; R-TST: R2= 0.9797, y= 1.085x + 0.3119; S-TST: R2= 0.9556, y= 1.124x + 0.0917). Assessment of specimens with low concentrations (< 3 nmol/L by MS, n=41) found that correlations were similarly poor between immunoassay methods and highest for B-TST (B-TST: R2= 0.5883, y= 1.259x + 0.3866; R-TST: R2= 0.4460, y= 0.9681x + 0.2760; S-TST: R2= 0.5449, y= 0.6352x + 0.3202). The root mean squared error (RMSE) was also calculated for the low concentration specimens and was significantly lower for S-TST than B-TST or R-TST (B-TST: 0.6708 nmol/L; R-TST: 0.6872 nmol/L; S-TST: 0.3698 nmol/L).

Conclusions

In patients where we expect low testosterone levels, MS continues to be the standard of care and immunoassays do not compare robustly at levels below 3 nmol/L. However, in cases where clinical decision making requires faster turn-around-time screening by immunoassay may be feasible. Clinical laboratories should be aware of the performance of their testosterone immunoassay methodologies at low testosterone concentrations as performance may vary between manufacturers. Manufacturer participation in the CDC HoSt program may provide additional performance information for clinical laboratories. Additional work is needed to assess performance across a larger cohort and additional immunoassay manufacturers.
A-035 Profiling of circulating-microRNAs' signatures in Pre-diabetic versus Diabetic patients
Authors: Rashid G , Abu-Toamih Atamni H , Sultan M
Published: October 2024

Background

MicroRNAs (miRs) are small non-coding RNAs involved in the process of gene regulation, and hence affect various diseases including metabolic pathways in diabetes. Given their key roles, they are promising candidates as potential biomarkers or better understanding of disease etiology. In this study, our aim is to identify miRs signatures of plasma circulating-miRs related to glycemic control, vitamin D deficiency and platelet activation in diabetic, pre-diabetic versus non-diabetic patients.

Methods

Plasma samples were collected from 24 patients (both sexes) in total (eight non-diabetic (ND) control, twelve diabetic (DM), and four pre-diabetic (PD)), classified based on their glycemic control (HbA1c levels). miRs were extracted using the miRNeasy Serum/Plasma Advanced kit of Qiagen, run and analyzed on Next Generation Sequencing (NGS).

Results

Differential expression analysis revealed miRs expression variations between diabetic to pre-diabetic and non-diabetic groups. Expression levels of 131 miRs varied significantly between DM to ND group (92 down- and 39 up- regulated), and 141 miRs in PD compared to ND (97 down- and 39 up- regulated). Although DM and PD had similar differential expression, three miRs (has-miR4776-5p, -6778-3p, and 5002-3p) were over-expressed in PD with very low p-value. Differential expression comparisons accounting sex were performed showing significant differences between males to females that will be presented here.

Conclusions

Our findings supports the important involvement of circulating miRs in the regulation of glucose homeostasis and pathogenesis of diabetes.Further investigation of candidate miRs could identify promising new biomarkers for the early diagnosis and prevention of Diabetes and related health complications.
A-039 Parathyroid Hormone and Vitamin D Follow an Inversely Correlated Serum Level
Authors: Islam S , Swift T , Sorce J , Hashim I A
Published: October 2024

Background

Parathyroid hormone (PTH) is a polypeptide responsible for regulating the physiological level of serum calcium through a complex homeostatic process closely associated with bone metabolism. In response to a decreased serum concentration of calcium, PTH level is increased leading to the elevation of calcium via bone resorption. Furthermore, Vitamin D (Vit-D) is a critical component of the endocrine system that also contributes to calcium homeostasis. Vit-D increases the level of serum calcium by stimulating intestinal absorption and renal reabsorption. Vit-D impacts the serum level of PTH by two distinct mechanisms. First indirectly, an increase in serum concentration of calcium, caused by Vit-D-mediated intestinal absorption and renal reabsorption disengages the process of PTH release through interaction with calcium-sensing receptors on parathyroid cells. Secondly, Vit-D directly interacts with parathyroid cells resulting in a reduced expression of PTH. Taken together, Vit-D is assumed to negatively impact the serum level of PTH. This study examined the homeostatic correlation between the circulating concentrations of Vit-D and PTH.

Methods

Retrospective serum concentrations of PTH and Vit-D were retrieved from the biochemical profiles of hospitalized and ambulatory patients who presented to or admitted at the tertiary care level hospital of University of Texas Southwestern Medical Center during the period between July-to-September of 2021. Correlation analysis between Vit-D and PTH was performed using GraphPad-PRISM-version-8.

Results

A total of 163 corresponding serum Vit-D and PTH values were obtained. Vit-D and PTH values displayed an inverse correlation (Figure 1). Pearson r values for linear and logarithmic trendlines (-0.6745 and -0.785, respectively) demonstrated a negative correlation between Vit-D and PTH.

Conclusions

Measuring Vit-D and PTH levels are critically important for assessing the homeostatic status of calcium. PTH level maintains an inverse relationship with Vit-D. Therefore, therapeutic targeting of Vit-D or PTH would mutually affect their concentration eventually reflected in calcium homeostasis.
A-040 Association of GATA-4 and Platelet Derived Growth Factor-B in Metabolic (Dysfunction) Associated Fatty Liver Disease
Authors: J H , Arulselvi S , Shalimar D , Vikram N K , Pandey S , Meena S , Prakash S
Published: October 2024

Background

Metabolic (dysfunction) associated fatty liver disease is a global concern as its prevalence is rising steeply ranging from 38.7% to 50.7%. MAFLD is a multifaceted burden of diseases such as diabetes, obesity, and cardio-metabolic diseases. It is the leading cause of hepatocellular carcinoma. GATA-4 is a zinc finger transcription factor located in liver sinusoidal endothelial cells and plays a critical role in liver regeneration. Platelet-derived growth factor-B (PDGF-B) plays a role in the profibrogenic trans-differentiation of Hepatic stellate cells and is actively involved in the development of hepatic fibrosis. Therefore, the study hypothesized that GATA-4 and PDGF-B are dysregulated and involved in the progression of MAFLD. Thus, the study aimed to assess the association of GATA 4 and PDGF-B in MAFLD, disease control, and healthy control.

Methods

80 subjects were recruited after exclusion criteria from Gastroenterology and Medicine OPD at AIIMS, New Delhi, and divided into 3 groups: Group 1 (healthy control)-20, Group 2 (disease control)-20, and Group 3 (MAFLD)-40. Institutional ethical committee approval was obtained. The demographic and anthropometric details, blood investigations, Non-invasive scores (AST/ALT ratio, APRI & FIB-4), and Transient elastography findings were illustrated in all the groups. The correlation between the GATA-4, PDGF-B, and platelet indices (MPV, P-LCR, PDW, and PCT) was done. STATA version 15 software was used for statistical analysis.

Results

GATA 4 was significantly decreased (p<0.001) and PDGF-B (p<0.001) was significantly increased in MAFLD subjects compared to healthy controls. However, no significant correlation was observed between GATA-4 and PDGF-B with platelet indices (P-LCR, PCT, and PDW). In contrast, mean platelet volume (MPV) was statistically significant (p<0.001) but it was clinically insignificant between the study groups. Similarly, HOMA-IR and GATA-4 did not show any significant correlation among MAFLD. However, CAP, LSM parameters of Transient elastography, APRI, and FIB-4 scores were statistically significant (p<0.001) in MAFLD when compared to healthy control. AUROC of non-invasive scores were found with weak discrimination and clinically not robust to distinguish the fibrosis grading.

Conclusions

GATA-4 and PDGF-B could be potential biomarkers, as no drugs are available so far to fill the global gap. However, pharmacological aspects need to be formulated for the treatment of MAFLD.
A-051 Validation and Implementation of the Stanbio Beta-Hydroxybutyrate Assay on Roche c502 Analyzer
Authors: Nogier K , Kalra J , Lu S , Wu F
Published: October 2024

Background

β-hydroxybutyrate (βOHB) serves as a crucial biomarker in assessing, managing, and monitoring ketosis in various clinical scenarios, such as diabetic ketoacidosis and instances of alcohol abuse combined with starvation. This study aimed to validate a βOHB assay (Stanbio Laboratory) conducted on a Roche Cobas c502 analyzer and establish performance specifications. Additionally, we conducted a method comparison for three assays: Randox D-3-Hydroxybutyrate (Ranbut) assay on Roche c501 analyzer, Abbott Freestyle Precision B-Ketone strip point-of-care test, and the Stanbio Laboratory β-Hydroxybutyrate LiquiColor assay on Roche c502 analyzer.

Methods

Precision, linearity, limit of quantification (LOQ), method comparison, and sample stability were determined according to Clinical and Laboratory Standards Institute (CLSI) guidelines, using commercial quality control materials (Randox Multisera) and residual patient samples (Lithium heparin anti-coagulated plasma). The reference interval was verified by residual samples from 20 healthy individuals (normal blood glucose, HbA1c, liver enzymes, and lipid panel results). Statistical analysis was performed by EP-Evaluator (v12).

Results

Intra-assay and total coefficient of variation (CV) were determined as 0% and 2.4% at 0.3 and 1.21 mmol/L, respectively. The linearity range of the assay was verified from 0.0 to 9.0 mmol/L. Using CV < 20% as criteria, the functional sensitivity (LOQ) was 0.10 mmol/L at least. Lithium heparin anti-coagulated plasma specimens were stable for 24 hours at room temperature or seven days at 4 - 8 ̊C. The manufacturer’s reference interval was verified as 0.00 - 0.40 mmol/L. The Stanbio βOHB assay on the Roche c502 analyzer demonstrated a strong agreement with the Randox D-3-Hydroxybutyrate assay on the Roche c501 analyzer with a slope of 1.053 (95% CI: 1.037, 1.070) and intercept of -0.005 (95% CI: -0.068, 0.059) (coefficient correlation R = 0.9992). A positive bias was observed compared to the Abbott Freestyle Precision B-Ketone strip POC test (mean bias = + 0.50 mmol/L; slope = 1.630, 95% CI: 1.404, 1.857; R = 0.9184), and this discrepancy occurred particularly at βOHB > 5.5 mmol/L measured by Abbott method.

Conclusions

The Standbio βOHB assay exhibited excellent precision and linearity across a brand range of concentrations. This assay strongly agrees with the Randox assay run on a similar instrument but discordance with Abbott’s POCT method at high βOHB concentration. Overall, the validated method provides a reliable and efficient means for measuring βOHB levels on a Roche chemistry analyzer, facilitating accurate diagnosis and monitoring of ketosis-related conditions in clinical settings.
A-057 Assessing Direct Renin Stability in EDTA Plasma Prior to Separation from Cells and Post-thaw
Authors: Troike K , Boyert N , Dee M , Colón-Franco J M
Published: October 2024

Background

Renin is an enzyme secreted by the kidneys responsible for blood pressure regulation through the renin-angiotensin-aldosterone axis. Direct renin measurements are frequently used to investigate underlying causes of hypertension, including primary aldosteronism (PA), which is screened for using an aldosterone:renin ratio (ARR). Appropriate handling of renin samples in the preanalytical phase is critical, as cryoactivation of prorenin can occur when samples are refrigerated or cooled for extended periods of time, falsely elevating results. Manufacturer instructions for renin handling are often poorly defined and there is currently no consensus as to best handling practices. Two variables that frequently lead to renin sample rejections in our laboratory are time to centrifugation after collection and time kept at room temperature (RT). The objective of this study was to evaluate the stability of direct renin under ambient and freeze-thaw conditions in an effort to reduce test cancellations due to improper handling.

Methods

Plasma samples collected from five volunteers with consent in K2EDTA tubes were used for renin stability studies. Baseline renin samples were kept at RT for two hours after collection, centrifuged, measured, and subsequently frozen for post-thaw studies. To assess stability before separation from cells, samples kept at RT for two and four hours prior to centrifugation were assayed in triplicate for direct renin. For post-thaw stability studies, plasma samples were split into two aliquots each and frozen at -20⁰C for at least 24 hours, but no longer than 30 days. After removal from -20⁰C, one set of aliquots was thawed on the benchtop at RT and the second set was thawed in an RT water bath for up to one hour. Samples were centrifuged and assayed for direct renin in triplicate at baseline and six hours post-thaw. Direct renin was measured using the LIAISON XL chemiluminescent immunoassay (Diasorin). Bias was assessed after each treatment. The total allowable error (TEa) was ±2 pg/mL or ±20%.

Results

Measured renin concentrations ranged from 6.8-29.7 pg/mL. The percent bias in direct renin concentrations when comparing samples stored for two-hour and four-hour timepoints before centrifugation was 2.0% on average. Post-thaw studies comparing renin concentrations at the baseline and six-hour timepoints revealed an average percent bias of 13.1% and 12.2% for RT and water bath thawing methods, respectively. All samples tested were within the TEa.

Conclusions

Direct renin is stable in lavender K2EDTA tubes at RT for up to four hours, prior to centrifugation and separation from cells. Renin concentrations remained stable after storage at -20⁰C and thawing at RT for up to six hours, regardless of thawing method. By expanding direct renin stability criteria, we hope to reduce the number of cancellations due to preanalytical handling errors and prevent redundant phlebotomy for patients.
A-061 Analytical Performance and R55G Mutant Detection Ability of an Improved Thyroid-Stimulating Hormone Assay, TSH3-Ultra II, on the ADVIA Centaur Immunoassay System and the Atellica IM Analyzer
Authors: Rhea-McManus J , Plumer A , Arrode-Bruses G , Dubravcic T
Published: October 2024

Background

Measurement of thyroid stimulating hormone (TSH) is a critical tool for the investigation of thyroid disorders. Previous studies have demonstrated that some immunoassays are unable to detect TSH from patients with the R55G mutation in the TSHβ subunit. This study evaluated the analytical performance of the ADVIA Centaur® and Atellica® IM TSH3-Ultra II (TSH3ULII) assay and its ability to detect the R55G TSH mutant.

Methods

Limit of quantitation (LoQ) and linearity were determined as described in CLSI EP17-A2 and EP06, respectively. Precision and method comparison (MC) studies were performed with three reagent lots according to CLSI EP05-A3 and CLSI EP09c using native and contrived human serum and plasma samples. For precision, one aliquot of each sample was tested in duplicate in two runs per day >2 hours apart on each analyzer for ≥20 days. MC studies were performed by testing native human serum samples using ADVIA Centaur TSH3-UL assay (current TSH assay) and the newer ADVIA Centaur TSH3ULII assay. An additional MC was performed by testing native human serum samples with the TSH3ULII assay on both the ADVIA Centaur XP and the Atellica IM Analyzer. Samples from 61 patients with TSH results below the LoQ when using TSH3-UL were sequenced and confirmed to have the R55G mutant. Each of these samples was tested in duplicate using the ADVIA Centaur TSH3ULII assay.

Results

LoQ on both the ADVIA Centaur XP and the Atellica IM Analyzer was estimated to be 0.010 μIU/mL (mIU/L). Linearity was verified from 0.010 to 150.000 μIU/mL (mIU/L). ADVIA Centaur TSH3ULII repeatability %CVs ranged from 1.4 to 3.6% at 0.099 and 91.993 μIU/mL (mIU/L), and within-lab %CVs ranged from 2.3 to 6.2% at 4.908 and 91.993 μIU/mL, respectively. Atellica IM TSH3ULII repeatability %CVs ranged from 1.1 to 3.4% at 4.800 and 93.097 μIU/mL, and within-lab %CVs ranged from 2.2 to 4.6% at 0.103 and 93.097 μIU/mL, respectively. For the MC studies, slopes determined by the Passing-Bablock regression model were approximately 1 (0.96-0.97 range) across the sample interval tested. All TSH3ULII results from the 61 mutant patient samples were greater than LoQ, ranging from 0.864 to 23.443 μIU/mL (mIU/L).

Conclusions

Evaluation of the TSH3ULII assay using the ADVIA Centaur system demonstrated performance comparable to the commercially available TSH3-UL assay for LoQ, linearity, and precision, when using normal patient samples. TSH3ULII results on the Atellica IM Analyzer were comparable to the results obtained on the ADVIA Centaur XP. All 61 TSH mutant samples used in this study that had TSH values below the LoQ with the TSH3-UL assay, were detectable with the TSH3ULII assay. The data presented here demonstrate the ability of the TSH3ULII assay to detect the TSH in samples from patients with the R55G mutation.
A-062 Determination Neonatal 17-Hydroxyprogesterone Cutoff Levels for Congenital Adrenal Hyperplasia in Korea: 3 years' experience
Authors: Yoon Y , Park K
Published: October 2024

Background

Newborn screening for congenital adrenal hyperplasia (CAH) is a crucial practice with significant global adoption. While it offers substantial benefits, it also presents challenges due to high false positive rates, which can lead to mental strain for families and unnecessary hospital visits. Our research delved into the impact of birth weight (BW), gestational age (GA), and GA combined with sampling time on 17-hydroxyprogesterone (17-OHP) concentration. Specifically, we aimed to establish appropriate 17-OHP cutoff values for preterm, low birth weight weight (LBW), and sick newborns.

Methods

A total of 2,429 newborns born between October 2020 and January 2024 were screened for CAH. Samples were collected from neonates on a filter paper with a heel prick method. The 17-OHP concentration was measured by AutoDELFIA Neonatal 17-hydroxyprogesterone kit (PerkinElmer, Turku, Finland). This assay is a solid phase, time-resolved fluoroimmunoassay based on the competitive reaction between europium labeled 17-OHP and sample 17-OHP for a limited amount of binding sites on 17-OHP specific polyclonal antibodies. The 99.5 percentile was applied to the cutoff of 17-OHP for CAH.

Results

17-OHP concentrations in newborns with lower BW and GA were significantly higher than those in normal BW and term newborns. 17-OHP concentration showed a statistically significant negative correlation with BW (r = -0.512, p < 0.001) and GA (r = -0.578, p < 0.001). Not only the full-term subgroup, but also preterm subgroups had a same tendency of 17-OHP concentration decrease with increasing sampling time. Application of newly establishing 99.5 percentile cutoff criteria significantly reduced recall rates to 1.02%, 0.81%, and 1.45% according to each criterion of BW, GA, and GA with sampling time, respectively.

Conclusions

This research introduces novel 17-OHP cutoff values for preterm, low birth weight (LBW), and sick newborns in the context of congenital adrenal hyperplasia (CAH). We analyzed the distribution of these cutoff values, considering factors such as birth weight, gestational age, and the timing of sample collection. Notably, applying the newly established cutoff criteria led to a significant reduction in false positive rates. Our laboratory’s data can serve as a valuable reference for other institutions aiming to set appropriate cutoffs, thereby minimizing unnecessary follow-up tests and enhancing the efficiency of CAH screening. As we continue to accumulate additional data, further reserch in this field remains promising.
A-072 Growth hormone stimulation tests: experience of a large cohort from a Brazilian diagnostic medical center
Authors: Correa Wengerkievicz Lopes A , Munhoz M F , Schrank Y , Nakaguma M , Spina L D , Machado I F , Teles A C , Pieroni F B , Perozo A F , Cavalcante L L
Published: October 2024

Background

Growth hormone (GH) stimulation tests are used to diagnose short stature in children and to assess hypothalamic-pituitary axis in adults. The most frequently stimulation tests are: oral clonidine (CLO), insulin-induced hypoglycemia (ITT), glucagon (GLU) and exercise (EXE). Well-known side effects are hypotension, nausea and vomiting. The aim of this study was to evaluate side effects and intercurrences observed during the performance of GH stimulation tests and to identify their possible predisposing factors.

Methods

From April/2022 to May/2023, in a large private laboratory located in 8 different sites, 3,006 GH stimulation tests were performed, with 266 patients with two or more GH stimulation tests.

Results

Considering only patients aged < 18 years (95% of the tests), the mean age was 10.3 ± 2.7 years (median 10.6 years), with 62.5% being male. GH stimulation test was distributed as follows: 64% CLO, 27.6% ITT, 7% GLU and 1.4% EXE. Patients with a history of asthma, allergies, seizure and heart disease were reported in 3%, 1.7%, 0.9% and 0.6%, respectively. More than 2 punctures for venous access were necessary in 9.3% of the cases, particularly in CLO test. The age of patients submitted to GLU was significantly lower compared to CLO and ITT (9.5 ± 3.3 years vs 10.3 ± 2.7 years and 10.6 ± 2.6 years, p < 0.001). Side effects were noted in only 5.1% of the total tests (145/2,863 tests), most frequent in the GLU (50/197 tests, 25%) and none observed in the EXE. There was no correlation of reported side effects with age and weight. As expected, hypotension was more frequent in CLO (27%), not associated with the oral clonidine administered dose (0.1 or 0.150 mg/SC). Nausea and vomiting occurred in 23% of the GLU tests. Symptomatic hypoglycemia that needed glucose administration (oral or parenteral) occurred in 8% of the ITT. Cough was observed in 6 patients during CLO, with no previous history of asthma or allergies. There were no occurrences that hospital transfer was need.

Conclusions

GH stimulation tests are safe and rarely cause serious side effects, certainly due to the presence of a prepared team for promptly support.
A-074 A Laboratory Developed Serum Anti-Mullerian Hormone Electrochemiluminescent Immunoassay: Performance and Retrospective Analysis of Over 2.2 Million Tests in Females and Males Across Lifespan
Authors: Alfego D , Cheng C , Bastidas M , Bauer B , Chun K
Published: October 2024

Background

The quantification of serum Anti-Mullerian hormone (AMH), a glycoprotein dimer produced by granulosa cells of the ovarian follicle in females and by Sertoli cells of the testes in males, has clinical utility across lifespan in both females and males. AMH is most frequently ordered to assess fertility in females of reproductive age, where it correlates with ovarian reserve. The clinical applications of serum AMH beyond ovarian reserve assessment, especially in males, pediatric, and postmenopausal populations, include the investigation of peri-menopause transition, delayed or precocious onset of puberty, differential diagnosis of disorders of sexual development, the evaluation of male gonadal function, and as an ovarian tumor marker. The objective was to establish and validate a highly sensitive assay to quantify AMH and to use our database of more than 2 million tests to understand the clinical utility of measuring AMH across sex and lifespan.

Methods

A validated two-step electrochemiluminescence assay was used for the quantification of serum AMH. The analytical performance of the assay was assessed, including accuracy, precision, and dilutional linearity. ICD-10 codes ordered between 2012 and 2023 were retrospectively analyzed for each subgroup based on age and sex to determine test usage. The analysis includes results from 2,229,845 female and 10,362 male patients across lifespan.

Results

The AMH analytical measurement range (AMR) was determined to be 0.015 - 15.0 ng/mL with a maximum reportable concentration of 960 ng/mL when run on dilution. Both inter- and intra-assay standard accuracy and precision were ≤ ±15.4% bias and ≤ 11.0% CV for all levels. Inter- and intra-assay sample precision was ≤ 9.6% CV across the AMR. Samples diluted linearly and recovered within 80 - 120% of the expected values when diluted up to 64X. Analytical interference caused by icterus, lipemia, or hemolysis was not observed. The most common ICD-10 associated with AMH orders was for fertility testing in females of reproductive age. AMH was also ordered in females for evaluation of ovarian cancer, menstrual disorders, and PCOS. In males, common ICD-10 codes associated with AMH include delayed puberty, hypoplasia of the penis, fertility testing, hypogonadism, and childhood short stature.

Conclusions

This study demonstrates a highly sensitive assay for the quantification of serum AMH with clinical utility across sex and lifespan. Using retrospective data, we determined that in addition to being used primarily in fertility testing, AMH is also commonly used to evaluate and manage other endocrine disorders and malignancies, including disorders of sexual development, disorders of puberty, PCOS, male gonadal dysfunction, and granulosa cell tumors. This assay can aid in defining the clinically relevant age and sex-specific levels of AHM in non-fertility-related conditions.
A-082 Establishment of Infant Free T4 Reference Interval Through Indirect Methods
Authors: Wu Z , Bi C , Li E M , Schindler E I , Marcelli M I , Wong E C , Clarke N J
Published: October 2024

Background

Children require reference intervals distinct from adults and, based on their unique developing physiology, several intervals are often required to accurately reflect the distribution of expected results in a healthy pediatric population. The establishment of pediatric reference intervals has proven challenging. While consenting adults volunteer to contribute their biological material towards the development of a reference interval, well children usually do not have the occasion to get blood drawn and the smaller the child, the more significant the impact of phlebotomy. For these reasons, scientists have sought out other methods for determining pediatric reference intervals. As an alternative, indirect statistical methods may be applied to large data sets of laboratory test results to ascertain a reference interval. The Multi-Modal Decomposition (MMD) is an iterative indirect method that decomposes a mixture of multiple normal distributions into separate components using the expectation-maximization (EM) algorithm The objective of the current study, was to apply MMD to ascertain reference intervals for free T4 in infants.

Methods

The study population included infants ranging in age from 1 day to 60 days who had specimens submitted for free T4 testing involving equilibrium dialysis followed by LC-MS/MS in a commercial reference laboratory (Quest Diagnostics Nichols Institute, San Juan Capistrano, CA). MMD was performed on 25,271 de-identified free T4 results to establish the reference intervals that were validated by comparison against free T4 values obtained on 238 de-identified specimens submitted for acylcarnitine testing, the specimen were analyzed for TSH and only the in-range specimens were include for Free T4 reference interval analysis.

Results

MMD analysis demonstrated distinct reference intervals for the following ages: 0 to 6 days (1.8 - 6.1 ng/dL), 7 days to <2 weeks (1 - 4.4 ng/dL), 2 to <3 weeks (0.8 - 3.5 ng/dL), 3 to <4 weeks (0.8 - 3 ng/dL), and 4 to <8 weeks (0.7 - 2.8 ng/dL). The data did not support the use of separate intervals for male and female children.

Conclusions

MMD analysis demonstrated distinct reference intervals for the following ages: 0 to 6 days (1.8 - 6.1 ng/dL), 7 days to <2 weeks (1 - 4.4 ng/dL), 2 to <3 weeks (0.8 - 3.5 ng/dL), 3 to <4 weeks (0.8 - 3 ng/dL), and 4 to <8 weeks (0.7 - 2.8 ng/dL). The data did not support the use of separate intervals for male and female children.
A-083 Performance evaluation of Sentinel Diagnostics’ ACE assay on the Abbott Alinity c system and ARCHITECT c16000 System
Authors: Brambilla S , Assalini C , Frana E , Lucini R , Novati D
Published: October 2024

Background

The analytical performances of the Angiotensin Converting Enzyme (ACE) assay for quantitative determination of ACE activity in human serum and plasma have been evaluated on the Abbott Alinity c system and ARCHITECT c16000 System. ACE (dipeptidyl carboxypeptidase) is a glycoprotein peptidyldipeptide hydrolase that cleaves histidylleucine dipeptide from angiotensin I, a relatively inactive decapeptide. The latter is converted to the potent vasoconstrictor, angiotensin II. ACE also inactivates bradykinin. Elevated levels of ACE activity occur in serum of patients with active sarcoidosis, and occasionally in premature infants with respiratory distress syndrome, in adults with tuberculosis, Gaucher’s disease, leprosy, and in many other pathologic conditions involving lung and liver diseases.

Methods

ACE hydrolyses urylacryloylphenylalanine-glycylglycine (FAPGG) to furylacryloylphenylalanine (FAP) and glycylglycine. Hydrolysis of FAPGG results in a decrease in absorbance at 340 nm. The ACE activity in the sample is determined by comparing the sample reaction rate to that obtained with the Sentinel ACE calibrator. Performances evaluation have been done following the latest CLSI guidelines protocols available.

Results

Summary of the analytical performances for the tested assay is reported in table below.

Conclusions

Analytical performances of Sentinel Diagnostics’ ACE assay demonstrate that quantitative determination of ACE activity in human serum and plasma are suitable for the routine measurement of the analyte on Abbott Alinity c system and ARCHITECT c16000 System.
A-095 A New CO2 Assay with Concentrated Reagent Having Superior Onboard Stability on Mindray BS-2800M Analyzer
Authors: Wang J , Huang X , Jiang M , Dai J
Published: October 2024

Background

Measurement of total content of CO2 in serum or plasma can be used to assist in the diagnosis of various acid-base disorders. There are small amounts (about 0.04%) CO2 in the earth’s atmosphere, or more in an enclosed clinical laboratory space. The environmental CO2 could be dissolved into the CO2 reagent continuously, in particular at lowered temperature when it is opened and stored on the system, which leads an impact on CO2 assay performance. Presently, competitors mainly use additional inserts or with small opening of the reagent container to reduce the contact with air from reagent, to improve its onboard stability. Here, we designed a new CO2 assay by optimizing the reagent formulation with a new protection mechanism to reduce the amount of CO2 absorption to the reagent and improved its onboard stability. This study evaluated performances of the new CO2 assay on Mindray BS-2800M analyzer.

Methods

Mindray CO2 assay with concentrated reagent is based on PEPC (Phosphoenolpyruvate Carboxylase) enzymatic method. It is designed with an innovative mechanism of reagent formulations with a protective layer of chemical(s) on top of the reagent that prevents CO2 from entering the reagent and reduced its impact to its on-board stability. The onboard stability was conducted with a constant reagent consumption mode to simulate as it in clinical lab use. The onboard study used two levels of Quality Control materials and serum pools. According to CLSI protocols, the following assay performances were evaluated: onboard stability, precision, method comparison, linearity, and interference.

Results

On Mindray BS-2800M analyzer, Mindray CO2 assay demonstrated an excellent onboard stability. With uncapped reagent on the system, the stability is for 21 days without recalibration, with less than ± 5% deviation from day zero. In parallel onboard stability studies, with Roche CO2 reagent on Cobas c701 system, the relative deviation from day zero was found to be within ±10%; and other three manufacturers` results with deviation exceeded ±10% vs. day zero in 7 days. The linearity of Mindray CO2 assay was determined as from 2.0 to 50.0 mmol/L. Our CO2 assay correlated well with Roche CO2 on Cobas c701 (Mindray = 1.0032 * Roche - 0.0186, r≥0.99). The repeatability and with-lab CVs were ranged from 0.64% to 3.41%, respectively. There was no significant interference (<±10%), at CO2 concentration of 15 mmol/L with bilirubin up to 60 mg/dL,hemolysate up to 800 mg/dL, Intralipid up to 1000 mg/dL, triglycerides up to 1000 mg/dL.

Conclusions

On Mindray BS-2800M analyzer, the new CO2 assay demonstrated a good ability against environmental CO2 inference in 21 days of onboard time. The new CO2 assay also shown good performances in precision, correlation (accuracy) and anti-interference from endogenous substances. Therefore, we conclude that the new Mindray CO2 assay is suitable for routine clinical laboratory use.
A-096 A New Direct Bilirubin (DBIL) Assay with Enhanced Performance in Anti-hemolysis Interference on Mindray BS-2800M Analyzer
Authors: Wang J , He H , Long K , Jiang M , Dai J
Published: October 2024

Background

Serum bilirubin could be used to assess liver functions. Due to clinical importance, it is highly desired to have an accurate bilirubin test. However, there are circumstances where error could occur in bilirubin test results. In particular, the hemolysis interference is one of the major problems that could mislead the direct bilirubin results because of their relatively high occurring frequencies in the clinical laboratories. To resolve this issue and improve the accuracy for the direct bilirubin, we developed a new reagent formulation for DBIL assay that minimizes hemolysis interference. In addition, this reagent also shown good performance characteristics on Mindray BS-2800M Clinical Chemistry analyzer.

Methods

The new DBIL assay is a vanadate-oxidation method that bilirubin is gradually transformed to biliverdin because of oxidizing agent vanadate, resulting in decreasing of absorbance at 450 nm. Two-level calibration is used for this assay. DBIL concentrations are obtained from the calibration line with signals from the patient samples in the assay. Following CLSI protocols, basic assay performances were evaluated: interference, precision, linearity, method comparison and low end detection (LOB, LOD, LOQ).

Results

Hemolysis interference was tested in parallel with DBIL reagents from different IVD companies, Roche, Wako and Chinese domestic main-player companies, A, B, and C. The results showed that the reagents of A and B companies were significantly suffered from hemolysis interference with maximum bias exceeded -30%. Although there are some effects on the anti-hemolysis with DBIL reagents of Wako and C company, the DBIL reagent of Mindray was the best with less than -8% of impact when hemolysate hemoglobin was up to 1000 mg/dL (H index). The Diazo DBIL assay from Roche shown issue with hemolysis interference. The interference to our new DBIL assay from lipid (up to 1000 mg/dL) and ascorbic acid (up to 30 mg/dL) were also with less than ±10% impact. The precision study was run according to EP05A3 with two commercial controls (∼ 10 and 30 µmol/L) and three serum sample pools (∼ 6.8,17.1 and 342 µmol/L). The CVs of repeatability were ranged from 0.54% to 0.58% for controls and 0.24% to 0.88% for serum pools, respectively. The within-lab precision was below 2.5%. The analytical linearity was determined as from 0.66 µmol/L to 439.66 µmol/L. For low-end detection, the LOB, LOD and LOQ were 0.5,1.0 and 1.7 µmol/L, respectively. In addition, the Mindray (y) correlated well with the DBIL assay of Wako (x) reagent on Mindray BS-2800M system (y): y =0.9847 x+0.1301 (r =0.9997, n =400, sample range: 1.08 - 430.00 μmol/L).

Conclusions

The new Mindray direct bilirubin assay shown a good anti-hemolysis interference performance on BS-2800M system and demonstrated good performances in other assay characteristics. It is therefore suitable for use in clinical laboratories.