Chemiluminescent Immunoassay Research Articles

Diagnostic concordance of hematoxylin-eosin and Giemsa staining of gastric biopsies with chemiluminescent immunoassay for stool antigen detection to diagnose Helicobacter pylori infection.

Diagnostic concordance of hematoxylin-eosin and Giemsa staining of gastric biopsies with chemiluminescent immunoassay for stool antigen detection to diagnose Helicobacter pylori infection.

Immunogenicity and Determinants of Antibody Response to the BNT162b2 mRNA Vaccine: A Longitudinal Study in a Cohort of People Living with HIV

Background: The COVID-19 pandemic posed significant challenges worldwide, with SARS-CoV-2 vaccines critical in reducing morbidity and mortality. This study evaluates the immunogenicity and antibody persistence of the BNT162b2 vaccine in people living with HIV (PLWH). Methods: We monitored anti-SARS-CoV-2 Spike IgG concentration in a cohort of PLWH at five time points (T0–T4) using chemiluminescent microparticle immunoassays (CMIAs) at the baselined both during and after vaccination. In severely immunocompromised individuals, a boosting dose was recommended, and participants and IgG concentration were measured in the two subgroups (boosted and not boosted). Results: In total, 165 PLWH were included, and 83% were male with a median age of 55 years (IQR: 47–62). At T1, 161 participants (97.6%) showed seroconversion with a median of IgG values of 468.8 AU/mL (IQR: 200.4–774.3 AU/mL). By T2, all subjects maintained a positive result, with the median anti-SARS-CoV-2 Spike IgG concentration increasing to 6191.6 AU/mL (IQR: 3666.7–10,800.8 AU/mL). At T3, all participants kept their antibody levels above the positivity threshold with a median of 1694.3 AU/mL (IQR: 926.3–2966.4 AU/mL). At T4, those without a booster dose exhibited a marked decrease to a median of 649.1 AU/mL (IQR: 425.5–1299.8 AU/mL), whereas those with a booster experienced a significant increase to a median of 13,105.2 AU/mL (IQR: 9187.5–18,552.1 AU/mL). The immune response was negatively influenced by the presence of dyslipidaemia at T1 (aOR 4.75, 95% CI: 1.39–16.20) and diabetes at T3 (aOR 7.11, 95% CI: 1.10–46.1), while the use of protease inhibitors (aORs 0.06, 95% CI: 0.01–0.91) and being female (aOR 0.02, 95% CI: 0.01–0.32) at T3 were protective factors. Conclusions: The immunogenicity of the BNT162b2 vaccine in PLWH has been confirmed, with booster doses necessary to maintain high levels of anti-SARS-CoV-2 Spike IgG antibodies, especially in patients with comorbidities. These findings underline the importance of a personalized vaccination strategy in this population.

Facile Synthesis and Characterization of Fluorescent Polystyrene Nanospheres for Homogeneous Light-Initiated Chemiluminescence Immunoassay.

Homogeneous light-initiated chemiluminescence technology (LICA) is widely used in clinical diagnostics due to the advantages of high sensitivity, minimal reagent usage, and no need for washing. Luminescent microspheres receive singlet oxygen emitted by photosensitive microspheres to generate optical signals. Therefore,1O2-initiated luminescent nanospheres are crucial, but there are few reports on the preparation of 1O2-initiated luminescent nanospheres. Herein, monodisperse luminescent Eu/C-28@PS (Eps) nanospheres were prepared and optimized using chelate Eu (TTA)3phen and 4-(2-phenyl-5,6-dihydro1,4-oxathiin-3-yl)-N, N-ditetradecylbenzenamine (C-28) as probe dye via THF/water swelling-shrinking procedure. Various swelling parameters were studied to obtain the swelling conditions that produce the minimum particle size and narrow size distribution, which shows good results in uniform particle size distribution (~ 250nm, a PDI of 0.03), surface carboxylate content (1.18mmol/g), and BSA loading capability (129.8mg/g) in the case of 20mg total probe dosage and 2h of incubation at 40°C using 14% THF/water mixture as a co-solvent system. The composition of the entrapped probe has a gain effect on the 1O2-initiated fluorescent signal and the optimal ratio of Eu (TTA)3phen: C-28 (1:1) was obtained on a commercial analyzer using IgG and anti-human IgG as models in PBS buffer. These results indicate that monodisperse luminescent Eps nanospheres are suitable as light-initiated chemiluminescence sensors and have great application potential in early detection, screening tests, and prognostic evaluation of patients.

Differences in target organ damage between captopril challenge test-defined definitive-positive and borderline-range groups among patients with primary aldosteronism.

The new Japanese guidelines for primary aldosteronism introduce a category in the judgment of functional confirmatory tests that is called the "borderline range," which is rare in the other international guidelines. The clinical characteristics of this borderline group are not yet understood. To investigate whether this borderline group has any significant differences in terms of target organ damage, we used data from a Japanese nationwide registry (JPAS-II) of individuals with primary aldosteronism or essential hypertension to compare the borderline group with the definitive-positive group and the negative group. We analyzed the cases of 1785 patients based on their captopril-challenge test results. Since the JPAS-II database contains plasma aldosterone concentration values obtained based on both radioimmunoassay (n = 1555) and chemiluminescent enzyme immunoassay (n = 230) principles, we converted these values to their equivalents as if measured by chemiluminescent enzyme immunoassay and conducted all analyses under the simulated condition. Multicovariate-adjusted models revealed significant prevalance odds ratios for chronic kidney disease (2.01, 95% confidence interval: 1.13 to 3.61), electrocardiographic abnormalities (1.66, 95% confidence interval: 1.16 to 2.37). No significant difference was observed between the borderline and negative groups in these assessments (odds ratio [95% confidence interval] for chronic kidney disease: 0.73 [0.26 to 2.02] and electrocardiographic abnormalities: 1.01 [0.60 to 1.70]). We confirmed that the prevalence of target organ damage increases linearly as the aldosterone-to-renin ratio rises following the captopril challenge test. These results provide material to consider regarding the significance of the provisionally established borderline group.

Comparison of five tacrolimus measurement methods underscore the need for a standardized method to improve clinical outcomes

Abstract Tacrolimus is a widely used drug to prevent post-transplantation organ rejection by suppressing host immune response. While its efficacy is well established, tacrolimus is also known for narrow therapeutic index and debilitating adverse effects, rendering accurate measurement for therapeutic drug monitoring essential, to minimize drug toxicity and graft loss, and maximize organ rejection prevention. Tacrolimus can be quantitated by immunoassay (IA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). However, previous pairwise studies showed significant inter-assay variabilities between different IA methods, and between IA vs LC-MS/MS, which may be associated with the fact that IA measures parent drug and its metabolites, while LC-MS/MS measures only parent drug. No clear conclusion has been drawn about the optimal method. Transplant patients may also have their tacrolimus levels measured at different laboratories by different methods, causing inter-laboratory and intra-individual variabilities which may affect tacrolimus dose adjustment and monitoring and lead to adverse clinical outcomes. Here we performed a multi-platform comparison of tacrolimus quantification by two IA and 3 LC-MS/MS assays. A total of 216 specimens were analyzed for tacrolimus levels using chemiluminescence immunoassay (ChLIA, ARCHITECT, Abbott Diagnostic) and electrochemiluminescence immunoassay (ECLIA, Elecsys, Roche Diagnostic), and three LC-MS/MS assays (assigned names LC-MS/MS A (Agilent), Q (Waters), and W (Agilent)) in five different laboratories at four institutions. In one laboratory, the same analyses were performed on two different individual instruments (LC-MS/MS W1 and W2). Comparative results using LC-MS/MS A as reference were analyzed using Deming regression analysis, Pearson correlation, Bland Altman plots and bias calculation using GraphPad Prism version 10.1.1. While the correlations between each method with the LC-MS/MS A were good (r value: lowest 0.948 (LC-MS/MS Q), highest 0.988 (LC-MS/MS W2)), the ChLIA and ECLIA showed positive absolute bias of 2.1 and 1.2 ng/mL, respectively, and proportional bias of +26% and +17%, respectively. In comparison, the absolute bias of LC-MS/MS Q, W1 and W2 were -0.7, -0.02, and -0.1 ng/mL, respectively, with proportional bias of -11%, -0.2%, and -0.7%, respectively. The LC-MS/MS platforms showed tight agreement with one another, while IA methods were noticeably different, both from each other and from the LC-MS/MS, with a consistent positive bias, more pronounced with the ChLIA than the ECLIA. Here, our data-driven approach demonstrated that LC-MS/MS is superior to IA, and among IAs, ECLIA showed higher accuracy compared to ChLIA. However, inter-assay differences remain, emphasizing a need for tacrolimus assay standardization as well as prospective clinical trials to identify the most optimal method of tacrolimus measurement and improve patient outcomes.

The Prospect of Improving Pancreatic Cancer Diagnostic Capabilities by Implementing Blood Biomarkers: A Study of Evaluating Properties of a Single IL-8 and in Conjunction with CA19-9, CEA, and CEACAM6.

Background/Objectives: This study aims to evaluate the possible clinical application of interleukin 8 (IL-8) as a single biomarker and its capabilities in combination with carbohydrate antigen (CA19-9), carcinoembryonic antigen (CEA), and carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) as diagnostic and prognostic tools for pancreatic ductal adenocarcinoma (PDAC). Methods: A total of 170 serum samples from patients with PDAC (n = 100), chronic pancreatitis (CP) (n = 39), and healthy individuals (n = 31) were analysed. IL-8 and CEACAM6 were measured by an enzyme-linked immunosorbent assay (ELISA). CA19-9 and CEA were determined by chemiluminescent microparticle immunoassay, and bilirubin was quantified using a diazonium salt reaction. Receiver operating characteristic curve analysis, logistic regression, and Kaplan-Meier analyses were performed to evaluate the properties of a single IL-8 and in combination with other biomarkers. Results: The concentrations of IL-8 were statistically significantly higher in the PDAC group compared to the CP and control groups. Heterogeneous levels of IL-8 correlated with PDAC stages (p = 0.007). IL-8 had good and satisfactory diagnostic efficacy in differentiating PDAC from controls (0.858; p < 0.001) and patients with CP (0.696; p < 0.001), respectively. High and low expressions of IL-8 were not significantly associated with overall survival (OS) or disease-free survival (DFS). A combination of IL-8, CEACAM6, and CA19-9 reached the highest AUC values for differentiating PDAC from the control group. The best classification score between PDAC and the control group with CP patients was obtained by merging IL-8 and CA19-9 (0.894; p < 0.001). Conclusions: These results provide compelling evidence of IL-8 as a promising diagnostic biomarker. Nonetheless, due to the high complexity of PDAC, only the conjunction of IL-8, CA19-9, and CEACAM6 integrates sufficient diagnostic capabilities.

Serum collagen IV as a predictor for response to direct-acting antivirals hepatitis C therapy

ABSTRACT Althoughchronic hepatitis C (CHC) therapies based on direct-acting antiviral (DAA) agents safely improved treatment effectiveness, some cases do not obtain sustained virological response (SVR) and, thus, evaluating factors that may be related to treatment failure is very important. We aimed to evaluate the association of baseline serum collagen IV with DAA treatment failure in Egyptian patients with CHC. A total of 175 CHC patients (100 responders and 75non-responders tosofosbuvir/daclatasvir) were included. Collagen IV was assessed using sensitive chemiluminescent immunoassay. There was distinctly higher (P < 0.0001) collagen IV in non-responders compared to responder patients as the median (interquartile range) were 19.02 (13.4–25.2) vs.9.7 (7.2–12.3) µg/L, respectively. Collagen IV has a good ability for distinguishing nonresponders from responder patients (AUC = 0.890) with sensitivity of 92%, specificity 72%, PPV 71.1%, NPV 92.3% and accuracy of 80.6%. Collagen IV was correlated (p < 0.05) with decreased albumin (r=-0.266), elevated APRI (r = 0.288), and elevated FIB-4 (r = 0.281) scores. In conclusion,these findings suggested the remarkable role of baseline collagen IV in the prediction of HCV DAAs treatment response. Thus, however further studies are needed, its measurement may improve treatment duration and the disease control.

Development of an automated immunologic mass spectrometry (iMS) method to overcome matrix effect for quantification: Steroid hormones as the example

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) shows great promise in clinical application for its high specificity, high sensitivity and wide linear range for the determination of small molecules. However, its application in clinical laboratory is hampered by matrix effect of clinical samples which could greatly affect quantification accuracy and the difficulty to be automated for the traditional sample preparation procedures. Thus, new techniques which could achieve selective enrichment to minimize matrix effect and automatic sample preparation of mass spectrometry are needed. We developed an immunologic mass spectrometry (iMS) method to overcome matrix effect and its clinical application was demonstrated for automatic analysis of testosterone (T), progesterone (P) and estradiol (E2) in human serum simultaneously. Firstly, three monoclonal antibodies were coupled to magnetic beads for selective enrichment of target hormones from serum. The immunomagnetic beads were separated, washed and eluted automatically for LC-MS/MS analysis. Analytical performance of the iMS method was validated and compared with traditional LC-MS/MS and chemiluminescence immunoassay (CLIA). Hormone levels were measured for 160 pregnancy women at different gestational weeks. Results showed that target hormones could be selectively captured with absolute recoveries of 93.9%–110.8 %. Relative responses for high, medium and low concentrations of the hormones between serum and methanol solution were 98.0%–109.7 %, 92.2%–105.3 % and 91.7%–96.0 % for T, P and E2, respectively. Calibration curves prepared in methanol solution, BSA solution and blank serum showed good consistency for the iMS method. The automated iMS method could overcome matrix effect of LC-MS/MS and cross-reaction of CLIA. Matrix effect of the iMS method was negligible as high specificity of target hormone enrichment before LC-MS/MS analysis. Matrix-matched calibration standards were no longer necessary for accurate quantification, which was of great benefit for the clinical application of mass spetrometry.

Comparison of different ANCA detection methods in a predominantly MPO-ANCA-associated vasculitis cohort

We compared different antineutrophil cytoplasmic antibody (ANCA) detection methods using a predominantly myeloperoxidase (MPO)-ANCA-associated vasculitis cohort. Stored sera from 147 patients with untreated ANCA-associated vasculitis (AAV), including microscopic polyangiitis and granulomatosis with polyangiitis (n = 115 and 32, respectively), and 124 disease controls were tested for P-ANCA and C-ANCA with immunofluorescence (IIF), and for MPO-ANCA and proteinase 3 (PR3)-ANCA with different antigen-specific immunoassays: direct enzyme-linked immunosorbent assay (ELISA), chemiluminescent enzyme immunoassay (CLEIA), third-generation fluorescent enzyme immunoassay (FEIA), and latex turbidimetrical immunoassay (LTIA). In addition, MPO-ANCA and PR3-ANCA titers were calibrated using certified reference materials (CRMs). The sensitivities and specificities for AAV diagnoses were 95% and 94% (IIF), 86% and 98% (ELISA), 93% and 94% (CLEIA), 92% and 96% (FEIA), and 68% and 88% (LTIA). Dual IIF/antigen-specific immunoassay testing reduced diagnostic accuracies from 94% to 93%. The quantitative agreement between ANCA levels measured using CLEIA and FEIA and calibrated using CRMs was not good. In conclusion, this study demonstrated the high performance of antigen-specific immunoassays for AAV diagnosis in a predominantly MPO-ANCA-associated vasculitis cohort and suggested that the benefit of dual IIF/antigen-specific immunoassay testing is limited. Standardizing ANCA measurements using different immunoassays was difficult, even when using CRMs.

Development of a chemiluminescent immunoassay based on magnetic solid phase for quantification of homocysteine in human serum

BackgroundHomocysteine (HCY) is a sulfur-containing amino acid that is an independent or important risk factor for the occurrence of many chronic diseases and is one of the most important indicators for determining health risks. However, existing HCY detection methods do not meet the requirements of clinical diagnosis. Therefore, there is an urgent need to establish new detection methods to meet the needs of clinical detection.ResultsIn this study, we used the principle of competitive method to establish a new method for the determination of HCY in human serum using a chemiluminescent enzyme immunoassay in conjunction with a chemiluminescent assay instrument that uses magnetic microparticles as the solid phase of the immunoreaction. The established method achieved satisfactory results in terms of minimum detection limit, specificity, accuracy, and clinical application. The limit of detection was 0.03 ng/mL. The intra-assay coefficient of variation (CV) was 1.94–5.05%, the inter-assay CV was 2.29–6.88%, and the recovery rate was 88.60–93.27%. Cross-reactivity with L-cysteine ranged from 0.0100 to 0.0200 μmol/L, and cross-reactivity with glutathione ranged from 0.0100 to 0.200 μmol/L, all of which were less than the limit of detection (LoD) of this method. The linear factor R of this method was greater than 0.99.ConclusionsIn summary, the developed method showed a good correlation with the product from Abbott. A total of 996 clinical patients with cardiovascular diseases were evaluated using the method developed in this study.

Type 1 diabetes mellitus; ovarian reserve; anti-Müllerian hormone; ovarian function

BACKGROUND: Prolonged course of diabetes mellitus often leads to the development of vascular complications, insufficiency of ovarian function. The occurrence of diabetes mellitus in women before pregnancy (pregestational diabetes mellitus) it can have various adverse consequences for the mother, fetus, child and the course of pregnancy. Pregnancy planning in women with pregestational diabetes significantly improves the outcomes of pregnancy and childbirth. AIM: The aim of this study was to analyze gonadotropic and ovarian function parameters in patients with type 1 diabetes mellitus depending on the age of onset, duration and compensation level of the disease. MATERIALS AND METHODS: The patients included into this clinical prospective study were divided into two groups. The main group consisted of 216 patients with type 1 diabetes mellitus aged 18 to 39 years (mean age: 27.1 ± 3.1 years). The control group consisted of 30 healthy women of reproductive age. Chemiluminescent immunoassay was used to determine blood serum levels of anti-Müllerian hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, estradiol, testosterone, free testosterone, and sex hormone-binding globulin from day 2 to day 5 of the menstrual cycle. Serum progesterone levels were measured on days 20–23 of the menstrual cycle for three consecutive cycles. Glycated hemoglobin levels were also studied in the blood serum of patients with type 1 diabetes mellitus. All the patients underwent pelvic ultrasound examination to assess the cohort of antral follicles and ovarian volume. RESULTS: The average age of menarche in patients with type 1 diabetes mellitus who developed the disease at the age of under 10 years was 14.2 ± 1.2 years. This was higher than in the group of girls with the onset of the disease over the age of 10 years (13.5 ± 1.2 years) and in women of the control group (11.9 ± 1.1 years). When assessing the ovarian reserve in patients with type 1 diabetes mellitus, we found a decrease in anti-Müllerian hormone level and antral follicle count in the group of women with disease onset at the age of under 10 years. We did not find differences in the ovarian reserve parameters in patients depending on disease duration. Normogonadotropic normoprolactinemic ovarian insufficiency was detected in 154 (71.3%) of 216 patients, while the rest 62 (28.7%) women had an ovulatory menstrual cycle. In patients with anovulation, luteal phase deficiency and ovulatory menstrual cycle, we found no differences between the age of development of type 1 diabetes mellitus, its duration, glycated hemoglobin levels, total daily insulin dose and insulin dose per kilogram of body mass. In patients receiving intensive insulin therapy with continuous subcutaneous insulin infusion, glycated hemoglobin level was lower than in those receiving multiple dose insulin injection therapy. CONCLUSIONS: The average age of menarche in patients with type 1 diabetes mellitus is higher than in healthy women. The ovarian reserve parameters in patients with early onset of the disease, before 10 years of age, are lower than in patients who developed type 1 diabetes mellitus after 10 years of age. Duration of pregnancy planning period depends on compensation level of the disease and lasts from six to 12 months. This requires the doctor and patient to prepare for the implementation of reproductive tasks as early as possible, especially in patients whose disease onset occurred in pre-pubertal period.

The Relationship between Vitamin D and TyG Index in Prediabetes and Type 2 Diabetes Mellitus among an Indian Tribal Community: A Cross-Sectional Study

Background: Vitamin D deficiency is thought to increase the likelihood of insulin resistance (IR) and diabetes onset. The objective of this study was to examine the association between the triglyceride glucose (TyG) index and vitamin D levels in individuals with prediabetes and type 2 diabetes mellitus (T2DM) in the tribal community of India. Methods: This study included 270 participants, consisting of 90 individuals with prediabetes, 90 individuals with T2DM, and 90 control patients. Anthropometric and biochemical characteristics were evaluated in all participants. 25-hydroxyvitamin D [25(OH)D] levels were measured using a chemiluminescent immunoassay. The TyG index was computed as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)]/2. Spearman correlation analysis and linear regression analysis were performed to assess the relationship between the TyG index and 25(OH)D levels in people diagnosed with prediabetes and T2DM. The optimum cut-off value of the TyG index for detecting vitamin D deficiency was determined by receiver operating characteristic (ROC) curve analysis. Results: We observed a significant reduction in vitamin D levels in individuals with prediabetes and T2DM compared to those in the control group. However, the TyG index was significantly greater in individuals with prediabetes and T2DM than in controls. Statistical analysis revealed a significant negative correlation between the TyG index and 25(OH)D in both prediabetes and T2DM. Conclusions: The TyG index demonstrated a negative association with vitamin D levels and was identified as an independent predictor of vitamin D deficiency in individuals with prediabetes and T2DM.

Assessment of Alinity s Chagas® as a Primary Diagnostic Test for Chronic Chagas Disease in a Non-Endemic Area of Europe (Barcelona, Spain).

Chagas disease (CD) has become a worldwide problem due to globalization. In Europe, most cases are imported and are diagnosed in the chronic phase by two serological tests, as recommended by the World Health Organization. Chemiluminescent microparticle immunoassays (CMIAs) are an emerging alternative to the diagnostic standard. We aimed to validate the CMIA Alinity s Chagas® as a primary diagnostic test for chronic CD following its replacement of Architect Chagas®, with an amended signal-to-cut-off (S/CO) ratio of ≥6. Laboratory results and clinical data were collected retrospectively from 774 sera from an at-risk population tested for CD in Barcelona during 2020-2022. Negative results required no further testing, and those with a S/CO ratio ≥ 0.8 were confirmed by a second serological assay, according to the common practice. Four per cent of the samples (31/774) were determined to be seropositive by Alinity s, 93.5% of which (29/31) had an S/CO ratio ≥ 6. Almost all the samples could be directly classified by the corrected S/CO. Alinity s Chagas® was validated as a single test for chronic CD diagnosis by raising the S/CO to ≥6. Its implementation could provide faster results and help reduce CD underdiagnosis in non-endemic countries.

7337 High Parathyroid Hormone (PTH) Due To Immunoassay Interference

Abstract Disclosure: V.A. Mendpara: None. A.J. McShane: None. L.Z. Khan: None. Background: PTH levels are not always accurate. This case illustrates immunoassay interference in a female with markedly abnormal PTH values. Understanding immunoassay interference in diverse hormonal assessments can prevent diagnostic inaccuracies. Clinical Case: A 63-year-old female with osteopenia underwent serum parathyroid hormone (PTH) testing as part of a thorough bone evaluation. The initial PTH level revealed an abnormal level of 4008 pg/mL (normal range: 15 to 65 pg/mL). The follow-up PTH level with the same assay continued to result in elevated values of &amp;gt;5000 pg/mL. The medication list was negative for biotin use, which is a well-known interfering substance in the PTH assay. Clinical evaluation was negative for hyperparathyroidism symptoms, and thyroid/parathyroid ultrasound was normal, as were serum levels of phosphate, vitamin D, and calcium. No PTH values had been checked for patients in the past after an extensive review of prior records. The initial PTH testing used the Roche Elecsys PTH STAT assay. To investigate a potential immunoassay interference, the following studies were performed: First, the sample was diluted with polyethylene glycol (PEG) to precipitate large molecular weight proteins; second, the sample was treated with a commercial heterophilic blocking reagent (Scantibodies Laboratory); and lastly, the sample was assayed utilizing a different PTH vendor (Siemens Atellica, chemiluminescent immunoassay). The PEG and heterophilic blocking treatments resulted in significantly lower PTH concentrations of 895.6 and 40.7 pg/mL, respectively. We do not anticipate a change in PTH levels in samples supplemented with blocking reagents or PEG without interference. The result from Siemens’ assay was markedly lower at 43.4 pg/mL. Both the Siemens and Roche assays employ mouse antibodies; however, the antibodies are proprietary between the vendors. This results in potentially different anti-mouse antibody epitope targets. Due to a history of advanced ovarian cancer, the patient was taking Oregovomab, a murine monoclonal antibody, as therapy for her advanced disease. It is unclear if this medication resulted in assay interference, but it is possible. Discussion: In summary, the discrepancy in PTH assay results highlights the need to consider immunoassay interference, particularly in patients with a history of cancer on immunotherapy agents. Our case highlights the importance of the clinician’s review of medications when assessing patients. While prior PTH assays were not conducted before the patient started Oregovomab, the potential development of interfering antibodies warrants consideration. Clinicians should be vigilant for atypical results and collaborate closely with laboratory professionals, as detecting interfering substances can result in misdiagnosis. Presentation: 6/2/2024

12426 Performance Of Dehydroepiandrosterone-Sulphate In Diagnosing Mild Autonomous Cortisol Secretion: A Systematic Review And Meta-Analysis

Abstract Disclosure: J. Saini: None. B. Salama: None. S.R. Chacko: None. K. Yu: None. I. Bancos: None. Objective: Measurement of baseline dehydroepiandrosterone sulfate (DHEAS) is suggested by the guidelines in support of diagnosing mild autonomous cortisol secretion (MACS). However, evidence on the diagnostic accuracy of DHEAS in MACS is difficult to interpret due to differences in the diagnostic cutoffs, small sample size, and heterogeneous reference standards. We aimed to conduct a systematic review and meta-analysis of published literature to assess the performance of DHEAS in diagnosing MACS, as defined in the 2023 guidelines. Methods: A comprehensive search was conducted using several databases from each database’s inception to January 8th, 2024. Databases include Ovid MEDLINE (R) and Epub Ahead of Print, In-Process &amp; Other Non-Indexed Citations, and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Databases of Systematic Reviews, and Scopus. Only original studies of at least 20 participants were included. MACS was defined as post-dexamethasone cortisol &amp;gt;1.8 mcg/dL. QUADAS-2 was used to assess the risk of bias. Bivariate and random effects meta-analysis was used to generate pooled diagnostic accuracy estimates. Results: The initial search yielded 285 articles, and only 7 studies met the inclusion criteria. In 7 studies (1 from North America, 3 from Asia, and 3 from Europe), a total of 574 patients with MACS and 830 referent subjects (patients with adrenal tumors without MACS) were included. The mean age was specified only in 5 studies and was similar in patients with MACS (55.5 years) and referent group (53.3 years). Patients with MACS had a higher number of women (323/472, 68.4%) as compared to the referent group (352/658, 53.4%). DHEAS cutoffs studied included: lower cutoff of age-and sex-specific ranges (3 studies), 40 mcg/dL (3 studies), 60 mcg/dL (1 study), and 67.5 mcg/dL (1 study). With increasing DHEAS cutoff, sensitivity for MACS diagnosis increased, and specificity decreased. Most studies (4 studies) used the chemiluminescent immunoassay to measure DHEAS. A meta-analysis of studies using DHEAS cut-off between 40-70 mcg/dL was performed, with a pooled sensitivity of 68% (95% CI: 51-81) and a pooled specificity of 85% (78-89). The positive likelihood ratio was 4 (95% CI: 3-6; I2=36.94, P=0.175) and the negative likelihood ratio was 0.4 (0.3-0.6; I2=49.97, P=0.092). Most studies were at a high risk of bias for selection of patients, index, or reference standard. Conclusion: Based on limited heterogeneous evidence, measurement of DHEAS provides additional value in diagnosing MACS. Further larger diagnostic accuracy studies should explore various DHEAS cutoffs and consider assay variability. Presentation: 6/3/2024

8551 Comparability of Free Testosterone Measurements

Abstract Disclosure: H. Zhou: None. O. Sugahara: None. U. Danilenko: None. H.W. Vesper: None. Assessment of free testosterone (FT) has been recommended as a biomarker for diagnosis and management of hypogonadism and female hyperandrogenism. Reliable laboratory measurements are essential for properly diagnosing and treating these diseases. FT is currently measured using direct commercial immunoassays, assays using equilibrium dialysis (ED) or other separation techniques, or estimated by calculating free testosterone (cFT) using different formulas based on the levels of total testosterone and sex hormone binding globulin (SHBG). There are concerns about the accuracy and reliability of current methods that may negatively impact correct detection, treatment, and prevention in patient care. CDC’s Clinical Standardization Programs (CDC CSP) has developed an accurate, high throughput method using ED coupled with isotope dilution ultra-high-performance liquid chromatography tandem mass spectrometry (ED-UHPLC-MS/MS). The ED step uses an internationally recognized procedure and is performed in a custom designed dialyzer system that allows maintaining equal ratio of sample-to-buffer volume. The method uses certified pure primary reference material (National Measurement Institute-M914) as calibrator. The method has a limit of detection of 0.6 pg/mL, with an accuracy of ±5%, and precision less than 10% CV. The measurement range is 2 – 2000 pg/mL. The analytical performance of this method as well as other FT methods used in patient care was assessed using single-donor serum samples. The evaluated methods included two commercially available platforms utilizing Chemiluminescence Immunoassay or radioimmunoassay techniques, as well as six laboratory-developed assays using ED-LC-MS/MS. The results of the interlaboratory comparison study will help assessing the current level of agreement among FT assays, to identify potential factors causing differences among assays, and to assist with developing materials to improve the agreement among assays. Presentation: 6/1/2024

Development of a fully automated chemiluminescent immunoassay for the quantitative and qualitative detection of antibodies against African swine fever virus p72.

African swine fever (ASF), caused by ASF virus (ASFV), is a highly infectious and severe hemorrhagic disease of pigs that causes major economic losses. Currently, no commercial vaccine is available and prevention and control of ASF relies mainly on early diagnosis. Here, a novel automated double antigen sandwich chemiluminescent immunoassay (DAgS-aCLIA) was developed to detect antibodies against ASFV p72 (p72-Ab). For this purpose, recombinant p72 trimer was produced, coupled to magnetic particles as carriers and labeled with acridinium ester as a signal trace. Finally, p72-Ab can be sensitively and rapidly measured on an automated chemiluminescent instrument. For quantitative analysis, a calibration curve was established with a laudable linearity range of 0.21 to 212.0 ng/mL (R2 = 0.9910) and a lower detection limit of 0.15 ng/mL. For qualitative analysis, a cut-off value was set at 1.50 ng/mL with a diagnostic sensitivity of 100.00% and specificity of 98.33%. Furthermore, antibody response to an ASF gene-deleted vaccine candidate can be accurately quantified using this DAgS-aCLIA, as evidenced by early seroconversion as early as 7 days post-immunization and high antibody levels. Compared with available enzyme-linked immunosorbent assays, this DAgS-aCLIA demonstrated a wider linearity range of 4 to 16-fold, and excellent analytical sensitivity and agreement of over 95.60%. In conclusion, our proposed DAgS-aCLIA would be an effective tool to support ASF epidemiological surveillance.IMPORTANCEAfrican swine fever virus (ASFV) is highly contagious in wild boar and domestic pigs. There is currently no vaccine available for ASF, so serological testing is an important diagnostic tool. Traditional enzyme-linked immunosorbent assays provide only qualitative results and are time and resource consuming. This study will develop an automated chemiluminescent immunoassay (CLIA) that can quantitatively and qualitatively detect antibodies to ASFV p72, greatly reducing detection time and labour-intensive operation, and improving detection sensitivity and linearity range. This novel CLIA would serve as a reliable and convenient tool for ASF pandemic surveillance and vaccine development.

B-078 Serodiagnosis of Rheumatoid Arthritis Using the New Accentis Chemiluminescence Immunoassay Platform for Anti-CCP Antibody Detection

Abstract Background Rheumatoid arthritis (RA) is one of the most common autoimmune diseases and the most frequent chronic inflammatory arthropathy. Reliable diagnosis at the earliest possible stage is indispensable to keep the disease under control with suitable therapy and to prevent irreversible joint damage. Autoantibodies against cyclic citrullinated peptides (CCP) are a highly specific marker for RA with relevance for (differential) diagnosis, prediction and prognosis. In this study, we investigated the clinical and analytical performance of a newly developed anti-CCP chemiluminescence immunoassay (ChLIA) system. Methods Serum samples from 170 patients with clinically confirmed RA and from a control panel of 274 patients with other diseases were analyzed using the EUROIMMUN Anti-CCP ChLIA (IgG), which was processed on the fully automated random-access system Accentis (EUROIMMUN). The results were compared with those obtained with the EUROIMMUN Anti-CCP ELISA (IgG) with regard to sensitivity, specificity and inter-assay concordance. Results The ChLIA achieved a sensitivity of 71.2% (121/170) and a specificity of 97.4% (267/274), while the ELISA was less sensitive (67.5%, 114/170) and specific (96.4%, 264/274). The qualitative results showed positive and negative agreement rates between the two assays of 92.7% (115/124) and 95.9% (307/320), respectively, resulting in 95.0% (422/444) overall agreement and a kappa score (0.878) indicating near perfect agreement. Conclusions The new Accentis ChLIA showed improved sensitivity and specificity for the detection of anti-CCP antibodies compared to the corresponding ELISA. Given the enhanced clinical performance and the practical benefits of using a random-access system, this ChLIA platform can effectively support the diagnosis of RA.

B-030 Performance evaluation of Siemens Atellica® IM Anti-Müllerian Hormone Assay

Abstract Background Anti-Müllerian hormone (AMH), a glycoprotein dimer, is produced by ovarian granulosa cells and its levels have been shown to directly correlate to the number of eggs remaining in the ovaries (ovarian reserve). Thus, measurements of AMH are widely used as an aid in the assessment of the ovarian reserve in women presenting to fertility clinics. This study aimed to evaluate the performance of the Siemens Atellica® IM AMH assay and compare it to the Beckman Access AMH assay. Methods The Atellica AMH assay is a fully automated chemiluminescent monoclonal sandwich immunoassay, while the Beckman Access AMH assay is also an automated chemiluminescent monoclonal sandwich immunoassay. Precision and linearity were assessed for the Atellica AMH assay using manufacturer-provided standards. Inter-laboratory correlation studies were completed using deidentified patient samples collected from 120 reproductive-age women undergoing fertility outpatient evaluation at Yale New Haven Health. Blood was drawn on the first office visit for fertility workup. AMH values were initially performed at Yale University using the Beckman Access AMH assay. Serum samples were then frozen (-20°C) and shipped on dry ice to the laboratory at the Ohio State University where they were thawed and analyzed using the Siemens Atellica AMH assay. Linear regression was employed for data analysis. Overall percent agreement using an AMH cut-off value of 1.77 ng/mL was calculated. AMH values &amp;gt;1.77 ng/mL were classified as positive and values ≤1.77 were classified as negative. Results The Siemens Atellica AMH assay exhibited good performance across the measuring range, with intra-assay and inter-assay coefficients of variation (CVs) ranging from 1.4% to 3.2% and 2.5% to 6.0%, respectively. The assay demonstrated linearity over the four recommended ranges (0.043-24.0 ng/mL) without significant bias observed. The Access and Atellica AMH assays demonstrated good overall agreement of 97% and were well-correlated with a R2 value of 0.9721. Conclusions The AMH assay was validated and routinely measured in-house using the Atellica automated assay. The Siemens Atellica AMH assay performs well across its measuring range and shows good agreement with Beckman Access AMH at the AMH cut-off of 1.77 ng/mL.

B-291 Validation of a Simple Qualitative Immunoassay for 21 Drugs of Abuse in Meconium on a Single Biochip Array

Abstract Background Drugs use during pregnancy is a major social and medical issue, which may lead to significant pre- and post-natal complications, such as preterm birth and newborn mortality. Exposed newborns may have long-term behavioral, cognitive, and developmental problems. Accurate detection of in utero drug exposure is crucial for timely medical intervention for the newborn and the mother. Meconium is the ‘gold standard' matrix for detection of drugs in newborn which reflects drug exposure during pregnancy. This study aims to develop and optimize a clinical assay for simultaneous screening of 21 drugs in meconium using a custom biochip array. Methods Custom biochip array (Randox Laboratories Ltd.) included 21 discrete test regions (DTRs) for amphetamine, methamphetamine, opioids/opiates (targeting morphine, oxymorphone, oxycodone, hydrocodone, 6-monoacetyl morphine, tramadol, buprenorphine, fentanyl, and methadone), phencyclidine (PCP), cocaine (targeting benzoylecgonine), benzodiazepines (targeting oxazepam, lorazepam, and clonazepam), zolpidem, barbiturates (targeting phenobarbital), ethyl glucuronide, methylphenidate, and marijuana metabolite (targeting Delta-9-Carboxy-Tetrahydrocannabinol [THC-COOH]). Patient samples were obtained from the residual meconium samples that had been previously used for other tests. Blank meconium samples were spiked at in-house cutoff, negative and positive assay control levels. All samples were extracted in specimen diluent using Biotage® Lysera and centrifuged. The supernatant was analyzed on a fully automated Randox Evidence+® Analyzer. A robotic arm pipetted 60 µL sample on to a biochip and then the analyzer performed a competitive chemiluminescent immunoassay. The results were generated as relative light units (RLUs). Results The sample results were determined to be “positive” or “negative” based on average RLU of cutoff controls for each analyte on an assay. The intra-assay (CV ≤ 15%) and inter-assay (CV ≤ 18%) precision was 100% agreement for positive and negative controls and there was no observed carryover for any of the analytes. The sample recovery was excellent with minimal to no matrix suppression for all analytes. Accuracy was performed by comparing spiked analyte results from Randox Evidence+® Analyzer with the expected results and all the spiked samples matched (positive or negative). When authentic patient or spiked results were compared with external laboratory test results, some discordant results were obtained. However, the discrepancies could be explained based on the different cutoffs (e.g., the Randox assay had lower cutoffs) or the known assay cross reactivities within the analytes of same class. These deviations did not affect clinical utility of the assay. Conclusions We validated a novel and simple qualitative chemiluminescent immunoassay in meconium using a custom biochip array. Unlike other routine screening/ELISA methods, which require separate assays for detection of similar drug targets, the custom biochip array offers a convenient, rapid and efficient method that utilizes only a single sample preparation for the screening of all 21 drug targets. Therefore, this technology has potential to be utilized as high-throughput screening assay. Like all qualitative assays, the limitation of this test is that all positive results will need to be assessed quantitatively for a definitive interpretation.