Chemiluminescent Immunoassay System Research Articles

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.

Evaluating the blood Serum Hormones, Cholesterol Levels in Seminiferous Plasma and Certain Semen Parameters in Males with Asthenozoospermia

Infertility is a medical condition that afflicts many men around the world and has many and complex causes. It is a malfunction in the male reproductive system. Its causes can be genetic, hormonal or a defect of semen components. This study was included two groups, the infertile (Asthinozoospermia) and the fertile or the control group (Normozoospermia), where each group consisted of 33 men average age (31.57 ± 1.11, 30.93 ± 1.04) respectively. Seminal fluid analysis (SFA) were conducted for them according to the recommendations of the World Health Organization (WHO), and the concentration level of cholesterol in seminal plasma was estimated using ELISA (Enzyme Linked Immuno-Sorbent Assay) and the concentration levels of blood serum hormones (FSH, LH, Prolactin, Testosterone) were estimated using the Chemiluminescence Immunoassay System (CL-900i) device. The study showed great convergence in the average age, BMI, semen volume and semen pH at asthenozoospermia group and Normazoospermia group, without a statistical significant difference (P>0.05). But there was a statistical significant difference (P<0.01) between Asthenozoospermia group and Normozoospermia group at sperm count, Progressive motility %, No-progressive motility % and immotile%. There was also, a significant difference between the two groups in the seminal plasma cholesterol concentration, (P<0.01). While there was no significant difference(P<0.05) between the two groups in the level of serum FSH, LH, Prolactin and Testosterone concentrations.

An automated magnetic beads-based chemiluminescence immunoassay system for simultaneous quantification of multi-mycotoxins in agricultural products

The coexistence of multiple mycotoxins poses a significant risk to the safety of agricultural products. Hence, a novel and automated magnetic beads-based chemiluminescence immunoassay (MCLIA) system was developed for the simultaneous quantification of typical multi-mycotoxins, including zearalenone (ZEN), Ochratoxin A (OTA), deoxynivalenol (DON), and aflatoxin B1 (AFB1). It comprises a compact chemiluminescence-based analyzer and a specially designed mycotoxin assay kit. Firstly, antimycotoxin monoclonal antibody (mAb) was coupled with alkaline phosphatase (AP), and the antigen of mycotoxin was then with biotin. After detailed optimization of this indirect competition immunoassay, all necessary reagents were preloaded and sealed into a specialized plastic reagent strip to prepare the assay kit. Secondly, a compact chemiluminescence-based analyzer was developed by programmatically integrating magnetic, thermal, and optical mechanisms. The MCLIA system facilitates the detection of mycotoxins in up to 8 samples simultaneously or various mycotoxins in different samples within 20 min, according to actual needs. The detection limits (LOD) for ZEN, OTA, DON, and AFB1 were 2.55, 0.64, 15.47, and 0.78 μg/kg, respectively, with the 50 % inhibition concentrations (IC50) in the ranges of 1.84−4.25, 0.95−1.69, 11.36−13.98, and 0.37−0.54 ng/mL. Parallel analysis of commercial agricultural products demonstrated a strong linear correlation (R2 = 0.9843–0.9962) with UPLC-HRMS, confirming the MCLIA system's reliability for the simultaneous quantitative detection of various mycotoxins. Offering advantages in detection sensitivity, dynamic range, and turnaround time, the compact MCLIA system facilitates automated and parallelized detection in the model of “sample-in to result-out”. It presents a versatile platform for the efficient immunodetection of other contaminants.

Pro-inflammatory cytokine IL-6 regulates LMO4 expression in psoriatic keratinocytes via AKT/STAT3 pathway.

The transcription factor LIM-only protein 4 (LMO4) is overexpressed in the psoriatic epidermis and regulates keratinocyte proliferation and differentiation. High LMO4 expression levels are induced by interleukin-23 (IL-23) to activate the AKT/STAT3 signaling pathway. Interleukin-6 (IL-6) is mainly involved in regulating T cell functions and development in patients with psoriasis. However, whether LMO4 expression is regulated by IL-6 remains unclear. Therefore, the purpose of this study is to explore the role and molecular mechanisms of IL-6 in regulating LMO4 expression. The interleukin-6 (IL-6) levels in human plasma were determined using a chemiluminescence immunoassay system. A psoriasis-like mouse model was established using imiquimod induction. Epidermal keratinocytes (HaCaT) were cultured in defined keratinocyte-serum-free medium and stimulated by IL-6 alone or with inhibitors. The proteins of interest were detected using western blot analysis, immunofluorescence, and immunohistochemistry. The 5-ethynyl-2'-deoxyuridine assay was used to detect cell proliferation. The results revealed that IL-6 levels were markedly increased in the plasma of patients with psoriasis, compared to healthy control. The high expression of LMO4 was consistent with high levels of IL-6, p-AKT, and p-STAT3 in the lesions of both psoriasis patients and imiquimod-induced psoriasis-like mice. IL-6 activates the AKT/STAT3 signaling pathway, followed by LMO4 high-expression in HaCaT cells. IL-6 induces HaCaT proliferation and differentiation via AKT/STAT3 signaling pathway activation. We think that the high expression of LMO4 in psoriatic keratinocytes requires IL-6 to activate the AKT/STAT3 signaling pathway and leads to epidermal keratinocytes abnormal proliferation and differentiation.

Ethno-demographic disparities in humoral responses to the COVID-19 vaccine among healthcare workers.

The COVID-19 pandemic had a profound impact on global health, but rapid vaccine administration resulted in a significant decline in morbidity and mortality rates worldwide. In this study, we sought to explore the temporal changes in the humoral immune response against SARS-CoV-2 healthcare workers (HCWs) in Augusta, GA, USA, and investigate any potential associations with ethno-demographic features. Specifically, we aimed to compare the naturally infectedindividuals with naïve individuals to understand the immune response dynamics after SARS-CoV-2 vaccination.A total of 290 HCWs were included and assessed prospectively in this study. COVID status was determined using a saliva-based COVID assay. Neutralizing antibody (NAb) levels were quantified using a chemiluminescent immunoassay system, and IgG levels were measured using an enzyme-linked immunosorbent assaymethod. We examined the changes in antibody levels among participants using different statistical tests including logistic regression and multiple correspondence analysis.Our findings revealed a significant decline in NAb and IgG levels at 8-12 months postvaccination. Furthermore, a multivariable analysis indicated that this decline was more pronounced in White HCWs (odds ratio [OR] = 2.1, 95% confidence interval [CI] = 1.07-4.08, p = 0.02) and IgG (OR = 2.07, 95% CI = 1.04-4.11, p = 0.03) among the whole cohort. Booster doses significantly increased IgG and NAb levels, while a decline in antibody levels was observed in participants without booster doses at 12 months postvaccination.Our results highlight the importance of understanding the dynamics of immune response and the potential influence of demographic factors on waning immunity to SARS-CoV-2. In addition, our findings emphasize the value of booster doses to ensure durable immunity.

Diagnostic Utility of Aldosterone/Direct Renin Concentration Ratio in Iraqi Patients with High Arterial Blood Pressure: A Pilot Study


 
 
 Objectives: Primary aldosteronism is a prevalent contributor to secondary hypertension, posing an elevated risk of morbidity and mortality. The initial step in diagnosing this condition involves screening individuals suspected of having it.
 Methods: In our study, we enrolled 50 patients who were suspected of having hyperaldosteronism. We provided specific recommendations and instructions to these patients concerning drug therapy and implemented measures to enhance testing accuracy. The tests were conducted using the Chemiluminescence Immunoassay (CLIA) system procedure, relying on plasma direct renin concentration rather than activity. Our findings were meticulously validated, compared, and aligned with the references from ARUP laboratories.
 Results: Among our participants, 4 patients (8%) were unequivocally diagnosed with primary aldosteronism based on the Aldosterone Direct Renin Concentration (ADRR) criteria. These patients exhibited the trifecta of hypokalemia, elevated aldosterone levels, and diminished renin levels, obviating the need for further confirmatory testing. Furthermore, 13 patients (26%) were deemed likely candidates for primary aldosteronism, given their plasma aldosterone levels exceeding 15 ng/dl and renin levels below 2.5 pg/ml. Additionally, 7 patients (14%) displayed strong indications of primary aldosteronism, characterized by plasma aldosterone levels surpassing 21 ng/dl and plasma renin concentrations below 2.5 pg/ml, accompanied by high ADRR values. However, both the "likely" and "strong indication" groups necessitated confirmatory testing. Notably, our results revealed no significant disparities in age, gender, personal or family history of atherosclerotic cardiovascular disease (ASCVD), or the presence of adrenal adenomas between patients diagnosed with primary aldosteronism and those in the non-aldosteronism group within the study.
 Conclusion: Primary aldosteronism is a prevalent health concern, warranting the screening of highly suspicious patients. Utilizing direct renin concentration, instead of renin activity, offers a straightforward, cost-effective, rapid, and reproducible method for diagnosis.
 
 

Automated and rapid chemiluminescence immunoassay for cardiac troponin I based on digital microfluidics

Rapid diagnosis of acute myocardial infarction (AMI) is critical in the clinical setting. An automated and rapid chemiluminescence immunoassay system based on digital microfluidics (DMF) is suggested for cardiac troponin I (cTnI). This method involves a double antibody sandwich structure. The cTnI antigen in the sample to be analyzed was captured by magnetic beads encapsulated with the cTnI antibody, which was subsequently recognized by the biotin-labeled secondary antibody. Horseradish peroxidase (HRP)-labeled streptavidin may be conjugated to biotin and used to mark the cTnI antigen because of the unique way that biotin binds to avidin. The simultaneous recognition of the cTnI antigen by primary and secondary antibodies in sandwich form, as well as the high specificity of the reaction between streptavidin and biotin, considerably improves the sensitivity and specificity of this technique for cTnI detection. This approach has decent stability. For cTnI samples, the full process took 40 min, with a limit of detection (LOD) of 0.34 ng mL−1. Additionally, there was a significant correlation range from 0.39 to 25 ng mL−1, with a correlation value of 0.994. The CV (Coefficient of variation) value was 2.26%. This system is anticipated to be used for the clinical measurement of cTnI in human serum.

5 Plasma cortisol responses of horses in equine assisted activities

Documentation of positive physical, social, psychological, and physiological outcomes in humans following interactions with horses has led to an increase of interest in and availability of programs offering equine assisted services (EAS). The effects of EAS programming and clients on horse well-being is unclear and needs further study given the increasing scrutiny the public sector gives to issues of animal welfare in the agricultural and equine industries. The objective of this study was to investigate the stress response of horses in equine assisted activities (EAA) via measurement of plasma cortisol. Horses were assigned to a 30 min adaptive horsemanship lesson with a veteran with posttraumatic stress disorder (PTSD) (EAA, n = 6, 20.3 ± 1.9 yrs, mean ± SE) or a concurrent 30 min standing control with no interaction in a small area of the same arena (CON, n = 6, 13.8 ± 1.7 yrs) such that horses served as conspecifics for one another with visual, olfactory, and auditory contact for the 8-week study. Lessons occurred weekly at the same time for a given pair of horses and veteran (between 1100 and 1500). EAA horses regularly participated in this type of work. CON horses were regularly ridden and handled by recreational riders. Indwelling jugular catheters were placed using sterile technique and local lidocaine anesthetic at least 30 min beforethe start of the lesson. Blood samples were collected into lithium heparin coated tubes at the start of the lesson (0), 3 min in (3), 5 min in (5), 25 min in (25), and 30 min in (30). Samples were immediately placed on ice until centrifuged at 2,500 rpm for 5 min. Plasma was aliquoted and stored at −80°C until assayed for cortisol using a solid phase chemiluminescent immunoassay system (Immulite) validated for use in horses. Data were analyzed using a mixed model ANOVA with fixed effects of treatment (EAA, CON), time point, week, and their interactions and a random effect of horse. Time point and week were considered repeated measures. Statistically different means were separated using Tukey's method. Significance was set at P ≤ 0.05. Cortisol concentrations during EAA ranged from 1.85 ± 0.26 µg/dL at time point 0 in wk 1 to 2.88 ± 0.30 µg/dL at time point 30 in wk 8 with no significant differences. Cortisol in CON horses was elevated at time points 25 (3.14 ± 0.19 µg/dL) and 30 (3.13 ± 0.19 µg/dL) as compared with time points 0 (2.56 ± 0.12 µg/dL), 3 (2.53 ± 0.13 µg/dL), and 5 (2.58 ± 0.14 µg/dL) (P ≤ 0.05). Horses appeared to be more stressed by confinement and limited contact with humans than by interactions with veterans with PTSD.

Effect of the third dose of BNT162b2 COVID-19 mRNA vaccine on anti-SARS-CoV-2 antibody levels in healthcare workers.

Administration of three doses of Pfizer-BioNTech BNT162b2 COVID-19 mRNA vaccine was completed in Japan in the spring of 2022. This study aimed to evaluate the antibody responses, and kinetics of three doses of vaccine in healthcare workers (HCWs). We conducted a longitudinal cohort study with HCWs, who had no history of COVID-19 or serologic evidence of SARS-CoV-2 infection, from a single hospital. Immunoglobulin G (IgG) titers of anti-SARS-CoV-2 spike protein (SP) and nucleocapsid protein (NP) titers were measured using an automated chemiluminescent enzyme immunoassay system. A total of 636 HCWs participated in the study. The anti-SP IgG titers decreased slowly after the second dose of the BNT162b2 vaccine in all participants, and robust antibody response was observed after the third dose of the vaccine. The peak anti-SP IgG titer after the third dose was approximately 4.1-fold higher than that after the first and second doses, and the rate of decrease in the anti-SP IgG titer after the third dose was significantly more gradual, than that after the second dose. After the second dose of vaccine, the antibody response was weaker in older participants than in younger participants, and in males than in females respectively, whereas the response to the third dose of vaccine did not differ significantly by sex or age. Adverse events following immunization were generally mild to moderate. The third dose of the BNT162b2 vaccine induced a significant and sustained increase in anti-SP IgG titers, and was generally safe and well-tolerated.

Comparison of Thyroid Functional Status among Different Levels of Glycaemic Status

Background: Diabetes mellitus (DM) is a leading cause of death and disability worldwide. Its global prevalence was about 8% in 2011 and is predicted to rise to 10% by 2030. Nearly 80% of people with diabetes live in low- and middle-income countries. Asia and the eastern Pacific region are particularly affected. In Bangladesh, which had a population of 149.8 million in 2011, a recent meta-analysis showed that the prevalence of diabetes among adults had increased substantially, from 4% in 1995 to 2000 and 5% in 2001 to 2005 to 9% in 2006 to 2010. According to the International Diabetes Federation (IDF), the prevalence will be 13% by 2030. Methods: This cross-sectional study was carried out on newly detected type-2 DM patients [n=200, m/f: 81/119; age: 41.1±8.3; BMI (kg/m2): 26.0±4.2; mean±SD] recruited consecutively from the department of Endocrinology, BSMMU. History and relevant clinical examination were recorded. Free thyroxine (FT4), thyroid stimulating hormone (TSH), anti-TPO and anti-TG antibody were tested Chemiluminescence Immunoassay System (Germany). Results: Highest frequency for positive anti-thyroid antibody (87.5%) was observed in group having TSH ≥10 m IU/L followed by 66.7% in the group having TSH (5-10) m IU/L, while only 2.8% in the group having TSH <5 m IU/L (p<0.001). There was no significant difference either for level of FT4 (14.0±4.5 vs 14.1±2.2 vs 13.9±1.5; p= 0.925) or for TSH (3.4±5.0 vs 3.7±9.7 vs 2.3±1.6; p= 0.691) or for the antibody status (p= 0.721) among different levels of HbA1c. No significant correlations of FPG, 2Hr75gPPG and HbA1c was found with any of FT4, TSH, anti-TPO and anti-TG antibodies (p= NS for all). Logistic regression revealed anti-TPO antibody as independent predictor for thyroid dysfunction in subjects with diabetes mellitus (p<0.001). Conclusion: A comparative study of thyroid hormone levels in diabetic and non-diabetic patients revealed that patients with type-2 DM had significantly lower serum FT3 levels ..........

Pediatric reference intervals for Free Testosterone, 17-OH Progesterone, Androstenedione, and IGF-1 with chemiluminescence immunoassay

BackgroundThe aim of the study was to produce age and sex specific pediatric reference intervals (RIs) on a fully automated chemiluminescent immunoassay (CLIA) system. Material and methodA total of 1586 patients’ remnant sera were included in the study and free testosterone (FT), 17-OH progesterone (17OHP), androstenodione (A4) and insulin-like growth factor-1 (IGF-1) parameters were measured on MAGLUMI 2000 (Shenzhen New Industries Biomedical Engineering Co., Ltd. (Snibe), Shenzhen, China) CLIA analyser. After appropriate age and gender partitioning, specific intervals were calculated according to Clinical Laboratory Standart Institute’s (CLSI) C28-A3 protocol. ResultsAll analytes showed sex and age dependent concentrations requiring several subgroups with specific reference intervals. 17OHP and A4 were found high with birth, declined thereafter: 17OHP by the end of 12 months and A4 by 6 months. So this period was also partitioned for these two hormones. All showed gradual increases by the end of 18 years. 17OHP, A4 and IGF-1 of girls were higher than boys around puberty as the result of earlier sexual development and maturation. FT values of boys and girls didn’t differ from each other upto 10 years of age but boys had significantly higher values than girls afterwards. IGF-1 values gradually increase in both sexes upto the ages of 13, girls with significantly higher values than boys. In 13–18 years no significant gender difference was found. ConclusionsWe present method specific pediatric RIs, which are comparable with medical literature, necessary for interpretation of patient results.

Anti-spike protein antibody responses to BNT162b2 mRNA vaccine: A single-center survey in a COVID-19 non-epidemic area in Japan

BackgroundThere are a few reports on antibody responses after a two-dose BNT162b2 vaccination in non-epidemic areas. We evaluated this phenomenon. MethodsA total of 344 healthcare workers were vaccinated, and the serum anti-receptor-binding domain (RBD) antibody concentrations before and after two weeks following the two-dose BNT162b2 vaccination were measured using electro chemiluminescence immunoassay system. ResultsBefore vaccination, the antibody titers of all participants were less than 0.6 U/mL. After two doses of the BNT162b2 vaccine injection in 342 participants (2 excluded), a high seroconversion rate (99.7%) was observed. The average (±standard deviation) serum anti-RBD antibody titers were 2324 ± 1739 U/mL. Antibody levels in females and males were 2443 ± 1833 U/mL and 1908 ± 1287 U/mL, respectively (p = 0.037). ConclusionIn a non-epidemic area, two BNT162b2 doses induced a satisfactory antibody response, and the antibody concentrations in females were higher than in males.

Serum Ferritin Concentration in Corona Virus Disease 19

Introduction: Coronavirus disease 19 (COVID-19) is a complex disease responsible for the development of exacerbated inflammatory response (cytokine storm) that ultimately leads to multiorgan failure and death. Serum ferritin has been recently identified as one of the inflammatory markers responsible for the pro-inflammatory effects. Small amount of ferritin is present in plasma (15-150 ng/mL) which might increase with the severity of COVID-19. Therefore, measurement of ferritin is essential in identifying disease severity and predict disease prognosis. Objective: This study aims to assess the ferritin level in COVID-19 patients. Methods: A cross-sectional study was carried out on 259 COVID-19 patients visiting KIST Medical College and Teaching Hospital (KISTMCTH), Lalitpur, Nepal from November 2020 to April 2021. Serum ferritin was estimated in the automated Siemens ADVIA Centaur CP Chemiluminescence Immunoassay system. All the patients visiting KISTMCTH referred by clinician for ferritin assessment were included in this study. Data collected using the proforma tool was tabulated in SPSS 21 and statistical analysis was done by inferential statistical test. Results: Out of total 259 COVID-19 patients, 58.7% were male and the majority of patients (82.6%) were below 70 years of age. The mean age for all participants was 52.11±16.59 years. Hyperferritinemia was seen in 218 (84.16%) COVID -19 patients. The mean value of serum ferritin was 767.1±789.86 (IQR: 12.8-4590) ng/mL and was significantly higher in males (p<0.001). Comparing the mean values of ferritin between the patients below and above 70 years, no statistical difference was observed (p=0.872). Conclusions: In our study, serum ferritin levels were greatly increased in patients with COVID-19 infection. Keywords: Coronavirus disease 19; cytokine storm; inflammatory marker; serum ferritin.

Analytical validation of the LiCA® high-sensitivity human thyroid stimulating hormone assay

BackgroundWe aimed to assess the analytical characteristics of a new high-sensitivity human thyroid stimulating hormone (hTSH) assay on a light-initiated chemiluminescent immunoassay system (LiCA Smart) and examine the utility of this assay in the context of profoundly low TSH levels (<0.01 mIU/L). MethodsAnalytical validations included precision, linearity, reportable range, analytical sensitivity, interference, reagent lot-to-lot and between-instrument variability, and method comparisons. Additionally, a cross-sectional study was performed to evaluate the assay for the detection of profoundly low TSH levels in comparison to those of two other ultrasensitive hTSH assays. ResultsWithin-run and within-lab imprecisions (%CV) were < 5% at all concentrations studied. A satisfactory linearity (R = 0.998, change in recovery < 5%) was verified over the entire measuring range. Method comparisons demonstrated a reasonable agreement (R > 0.99, median bias < 5%) between LiCA and Cobas, ADVIA, UniCel or Architect. The limit of quantitation was 0.0019 mIU/L. Comparative measurements of 236 patient samples with profoundly low TSH levels (<0.01 mIU/L) by LiCA, Cobas, and Architect revealed that the detection rate observed with LiCA (67.8%) was significantly higher than that with Cobas (28.0%) or Architect (21.7%). In a further comparative follow-up of patients with overt hyperthyroidism who were receiving treatment, an earlier recovery response of TSH was observed in LiCA. ConclusionsThe LiCA Smart hTSH is a precise and highly sensitive fourth-generation assay. The assay demonstrated superior detection sensitivity for profoundly low TSH levels and was acceptable for clinical use.

Antibody titers against the Alpha, Beta, Gamma, and Delta variants of SARS-CoV-2 induced by BNT162b2 vaccination measured using automated chemiluminescent enzyme immunoassay

BackgroundLevels of 50% neutralizing titer (NT50) reflect the a vaccine-induced humoral immunity after the vaccination against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Measurements of NT50 are difficult to implement in large quantities. A high-throughput laboratory test is expected for determining the level of herd immunity against SARS-CoV-2. MethodsWe analyzed samples from 168 Japanese healthcare workers who had completed two doses of the BNT162b2 vaccine. We analyzed immunoglobulin G (IgG) index values against spike protein (SP) using automated chemiluminescent enzyme immunoassay system AIA-CL and analyzed the background factors affecting antibody titer. SP IgG index was compared with 50% neutralization titers. ResultsThe median SP IgG index values of the subjects (mean age = 43 years; 75% female) were 0.1, 1.35, 60.80, and 97.35 before and at 2, 4, and 6 weeks after the first dose, respectively. At 4 and 6 weeks after the first dose, SP IgG titers were found to have positive correlation with NT50 titer (r = 0.7535 in 4 weeks; r = 0.4376 in 6 weeks). Proportions of the SP IgG index values against the Alpha, Beta, Gamma, and Delta variants compared with the original strain were 2.029, 0.544, 1.017, and 0.6096 respectively. Older age was associated with lower SP IgG titer index 6 weeks after the first dose. ConclusionsSP IgG index values were rised at 3 weeks after two doses of BNT162b2 vaccination and have positive correlation with NT50. SP IgG index values were lower in the older individuals and against Beta and Delta strain.

A Novel Thyroglobulin Immunoassay Using the Specimen-Pretreatment Process Improves the Accuracy of Thyroglobulin Measurements in Anti-Thyroglobulin Positive Specimens.

Recently, second-generation thyroglobulin (Tg) sandwich immunoassays have been used in clinical laboratories to measure the serum Tg levels, which is a tumor marker used to monitor postoperative patients with differentiated thyroid cancers. However, these immunoassays are often subject to Tg autoantibody (TgAb) interference. TgAb interference is inevitable for almost all Tg immunoassays, resulting in unreliable Tg measurement values of TgAb-positive samples. To address TgAb interference, we have developed a novel immunoassay based on a fully automated chemiluminescent enzyme immunoassay system using the effective specimen-pretreatment process to inactivate TgAb in blood and evaluated its assay performance. The developed assay was traceable to BCR457 IRMM reference material with a limit of quantification of 0.03 ng/mL. The pretreatment process inactivated almost all TgAb in specimens and allowed accurate Tg measurements in TgAb-positive samples in which TgAb interference was observed using the immunoassays. Size-exclusion chromatography analysis of immunoreactive Tg molecule in a TgAb-positive serum verified disruption of the Tg-TgAb immune complex by the pretreatment process. Good correlation of Tg values in TgAb-negative specimens was observed between the new Tg immunoassay and the second-generation sandwich immunoassays. However, there were numerous discrepant samples on bias plots between the new Tg immunoassay and the second-generation sandwich immunoassays for TgAb-positive specimens. This study indicates the new Tg immunoassay with the specimen-pretreatment process is both robust and free from interference by TgAb. Thus, this novel assay is superior to second-generation sandwich immunoassays and gives accurate Tg concentrations even for TgAb-positive cases.

English

BACKGROUND One of the most common causes of thyroid dysfunction among women is autoimmunity, especially in fertile age group. Thyroid hormone disorders are associated with a number of biochemical abnormalities including dyslipidaemia, metabolic dysfunctions, spontaneous miscarriage, and preterm delivery. Dyslipidaemia is one of the most common metabolic abnormalities present in patients with thyroid disease. The purpose of this study was to find the association between anti-thyroid peroxidase antibody (anti-TPO) and dyslipidaemia in reproductive age group females from Central Kerala. METHODS A total of 200 asymptomatic women, all in reproductive age group, from a tertiary hospital in Kerala participated in this study. Demographic data and detailed medical history of the participants were collected. Anti-TPO and thyroid stimulating hormone (TSH) were measured using chemiluminescence immunoassay system. Serum lipid profile was estimated using fully automated random-access clinical chemistry analyser EM - 360. Continuous variables were compared between the groups using Mann–Whitney U-test. P value lesser than 0.05 was considered as statistically significant. RESULTS The mean age of the subjects was 32.92 ± 11.82 years. A total of 47 participants (23.5 %) were anti-TPO positive. Abnormality in lipid profile was present in 72.34 % (N = 34) of the anti-TPO positive participants. In the anti-TPO positive group, 51.06 % of the participants had hypercholesterolemia. In the anti-TPO positive group, anti-TPO levels show a statistically significant correlation with total cholesterol and triglyceride levels (P = 0.07 and P &lt; 0.01). A total of 9 % (N = 18) had thyroid stimulating hormone (TSH) values greater than normal range (0.34- 4.25 µIU/mL) suggesting presence of hypothyroidism. TSH values were also significantly associated with lipid profile in the anti-TPO positive group. Both thyroid autoimmunity and dyslipidaemia can affect fertility, pregnancy and other reproductive outcomes. CONCLUSIONS Women should be screened for autoimmune antibodies and associated biochemical abnormalities to estimate and reduce the risk of cardiovascular morbidity, negative pregnancy outcomes and infertility. KEY WORDS Thyroid Autoimmunity, Anti-TPO Antibody, Dyslipidaemia

Reference intervals for preterm thyroid function during the fifth to seventh day of life

BackgroundDue to the lack of reference intervals for serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) in preterm neonates during the 5th to 7th day of life, we performed a retrospective study using the chemiluminescence immunoassay system. MethodsA total of 2040 preterm neonates with a gestational age (GA) of 26–35 weeks in the neonatal intensive care unit from 2014 to 2019 were included. Their serum FT3, FT4 and TSH values were calculated and analyzed to establish reference intervals for preterm neonates stratified by GA. The comparisons of FT3, FT4 and TSH were made by sex (males and females) and gestational age (26–28 weeks; 29–32 weeks; 33–35 weeks). ResultsThe reference intervals for FT3, FT4 and TSH in preterm neonates with a GA of 26–35 weeks were (1.65~5.21) pmol/L, (8.64~25.41) pmol/L, and (0.406~12.468) mlU/L, respectively. There were significant differences between serum FT3 and FT4 values and GA, while TSH levels were not significantly different (P < 0.01). The serum FT3 values of males were lower than those of females, especially in the 29–32 weeks group. No significant differences in serum values between sexes were found in FT4 or TSH (P > 0.05). ConclusionReference intervals of thyroid function tests were established to determine the early diagnostic criteria of thyroid diseases for neonates with a GA of 26–35 weeks and to avoid unnecessary retesting and interventions. The reference intervals of FT4 can be used as an indicator to regulate the doses of thyroid hormone supplement in the treatments of congenital hypothyroidism.

Performance of an Advanced Interferon-Gamma Release Assay for Mycobacterium tuberculosis Detection.

The LIAISON® QuantiFERON®-TB Gold Plus (QFT-Plus) assay, a fully automated chemiluminescence immunoassay (CLIA) system, has recently received FDA approval for the detection of interferon-γ (IFN-γ) on the LIAISON XL analyzer. Here, we evaluated the diagnostic performance of the LIAISON's CLIA method in comparison to the widely used ELISA method using the Qiagen QuantiFERON-TB Gold Plus Blood Collection Tubes. Heparinized blood samples from 329 participants were categorized into 3 cohorts, including 15 with confirmed tuberculosis (TB) (active TB cohort), 129 non-TB (low-risk cohort), and 185 potential TB (mixed risk cohort). Samples were analyzed with both assays and results were interpreted according to the manufacturers' criteria. The LIAISON CLIA assay showed an overall agreement with the Qiagen ELISA assay in 13/14 (92.8%) samples among the active cohort, 93/95 (97.9%) among the low-risk cohort, with a Cohen's kappa value of 0.76 and 0.74, respectively. Test results for 185 mixed risk cohort participants showed 97.8% agreement between the LIAISON and the Qiagen, with 17 positive, 163 negative, and 1 indeterminate. Four samples were discrepant; 3 of these were negative on the ELISA but positive on the CLIA assay. Overall, the results were comparable (>92% agreement) in our study cohorts. In addition, our mixed risk cohort results showed an excellent agreement of 0.88 (Cohen's kappa value) between the 2 assays. These findings suggest that the automated LIAISON QFT-Plus assay has a comparable diagnostic performance to the Qiagen assay and can be used for latent TB infection (LTBI) diagnosis.

Autopsy Cardiac Troponin I Plasma Levels Can Be Elevated in Myocardial Infarction Type 3: A Proposal to Modify the Definition of Myocardial Infarction Type 3.

The definition of myocardial infarction (MI) type 3 does not include the possible elevation of postmortem biomarkers if measured at autopsy. We determined postmortem cardiac troponin I (cTnI) levels in plasma samples obtained at autopsy in patients who died from MI type 3 to determine whether cTnI plasma levels may be elevated. Using a chemiluminescent microparticle immunoassay system, we determined postmortem cTnI plasma levels at autopsy performed within 24 hours of death in every decedent who died from MI type 3, confirmed by an autopsy. Over 2 years, autopsy confirmed 52 decedents who died from MI type 3 due to coronary atherosclerotic disease. The age range and mean age were 40 to 78 and 60.6 years, respectively, 38 (73%) men and 14 (27%) women. Ten percent of the decedents exhibited postmortem cTnI plasma levels that were within the normal reference levels (0.01-0.30 ng/mL). Ninety percent of the decedents exhibited elevated cTnI plasma levels at autopsy, which ranged from 0.31 to greater than 4400 ng/mL. Sixty-nine percent of our decedents showed severe/significant (75%-100%) luminal occlusion in 2 or 3 major coronary arteries. If cTnI plasma levels are measured in autopsy blood samples after sudden and unexpected death due to MI type 3, highly elevated cTnI plasma levels may be detected. We propose that the current MI type 3 definition be slightly modified to include the possible elevation of cTnI plasma levels if measured at autopsy in the immediate postmortem period.