Serum biomarkers correlated with liver stiffness assessed in a multicenter study of pediatric cholestatic liver disease.

BACKGROUND AND AIMS: Detailed investigation of the biological pathways leading to hepatic fibrosis and identification of liver fibrosis biomarkers may facilitate early interventions for pediatric cholestasis. APPROACH AND RESULTS: A targeted enzyme-linked immunosorbent assay-based panel of nine biomarkers (lysyl oxidase, tissue inhibitor matrix metalloproteinase (MMP) 1, connective tissue growth factor [CTGF], IL-8, endoglin, periostin, Mac-2-binding protein, MMP-3, and MMP-7) was examined in children with biliary atresia (BA; n = 187), alpha-1 antitrypsin deficiency (A1AT; n = 78), and Alagille syndrome (ALGS; n = 65) and correlated with liver stiffness (LSM) and biochemical measures of liver disease. Median age and LSM were 9 years and 9.5 kPa. After adjusting for covariates, there were positive correlations among LSM and endoglin ( p = 0.04) and IL-8 ( p < 0.001) and MMP-7 ( p < 0.001) in participants with BA. The best prediction model for LSM in BA using clinical and lab measurements had an R2 = 0.437; adding IL-8 and MMP-7 improved R2 to 0.523 and 0.526 (both p < 0.0001). In participants with A1AT, CTGF and LSM were negatively correlated ( p = 0.004); adding CTGF to an LSM prediction model improved R2 from 0.524 to 0.577 ( p = 0.0033). Biomarkers did not correlate with LSM in ALGS. A significant number of biomarker/lab correlations were found in participants with BA but not those with A1AT or ALGS. CONCLUSIONS: Endoglin, IL-8, and MMP-7 significantly correlate with increased LSM in children with BA, whereas CTGF inversely correlates with LSM in participants with A1AT; these biomarkers appear to enhance prediction of LSM beyond clinical tests. Future disease-specific investigations of change in these biomarkers over time and as predictors of clinical outcomes will be important.

Analytical and clinical performance of cPass neutralizing antibodies assay.

Serological tests for SARS-CoV-2 are a critical component of disease control strategies. SARS-CoV-2 serology tests used in clinical diagnostic should not accurately evaluate total levels the antibodies but also closely correlate with neutralizing antibodies titers. However, only limited data is available reporting correlation of neutralization antibody assays with commercial high-throughput serological assays widely used in clinical laboratories. We performed evaluation of the GenScript cPass neutralizing antibody detection assay, to assess its value for routine clinical use to measure neutralizing titers in patients who recovered from coronavirus disease 2019 (COVID-19) or have been vaccinated. We tested its clinical performance against the commonly used Ortho Vitros IgG assay. Our combined data shows that GenScript cPass neutralizing antibody assay has satisfactory analytical and clinical performance and good correlation with Ortho Vitros IgG, supporting its use as a tool for accurate SARS-COV-2 immune surveillance of recovered or vaccinated individuals.

Perioperative Procalcitonin in Predicting Infection in Children Undergoing Surgical Procedures.

BACKGROUND: Procalcitonin (PCT) is a biomarker of bacterial infections with more sensitivity and specificity than commonly used inflammatory markers. PCT can be particularly helpful in the postsurgical population where the surgery itself often leads to noninfectious inflammation. We aimed to examine the utility of perioperative profiles of PCT in predicting infection in two pediatric surgical populations. METHODS: We conducted a prospective observational study of perioperative PCT in children undergoing cardiac or neurosurgery. Consenting patients with no preoperative infection or immune deficiency were enrolled. We measured plasma PCT levels within 24 h preprocedure and 24-48 h postprocedure. Demographic, clinical, and laboratory data were collected from the medical records including clinical suspicion and confirmed infections. Perioperative PCT changes and their associations with these data are reported. RESULTS: We enrolled 26 neuro and 15 cardiac surgery patients. There was postoperative clinical suspicion of infection in 3 neuro and 5 cardiac patients, and 1 neuro and 2 cardiac patients had subsequently confirmed infections. Cardiac patients had higher overall perioperative PCT increase than neuro cohort (P = 0.006). Neuro patient with infection had higher perioperative change in PCT (0.5 to 1.4 ng/mL) than noninfected neurosurgery patients. Cardiac patients with confirmed infections had higher postoperative levels which exceeded the previously described infection threshold of 2 ng/mL. CONCLUSIONS: PCT is a useful early biomarker of postoperative infection in pediatric patients undergoing cardiac and neurosurgery. Patients who underwent cardiac surgery have significantly higher perioperative PCT rise than patients who underwent neurosurgery, and all patients with subsequently confirmed infections had at least 2-fold perioperative PCT increase.

Validation of the newly FDA-approved Buhlmann fCal Turbo assay for measurement of fecal calprotectin in a pediatric population.

OBJECTIVES: Inflammatory bowel disease (IBD) is an increasingly prevalent disorder marked by chronic intestinal inflammation. Fecal calprotectin has emerged as a useful biomarker for differential diagnostics and monitoring IBD activity. We validated the newly FDA-approved fCal Turbo fecal calprotectin assay in our pediatric hospital. DESIGN AND METHODS: The performance of the fCal Turbo assay was assessed on the Vitros 5600 analyzer (Ortho Clinical Diagnostics, USA), including limit of quantitation, linearity, precision, and interference studies. Method comparison was performed with 20 fecal samples with the Buhlmann fCal ELISA, and reference range verification was performed with 33 fecal samples. RESULTS: The fCal Turbo assay on the Vitros 5600 was linear between 33.1 and 14,182.5 â€‹µg/g, with dilution studies extending the range to 33.1-22,000 â€‹µg/g, Reproducibility of the assay met acceptability criteria, with intra-assay CV of 0.3-3.2% and inter-assay CV of 5.2-8.9%. Interference studies identified acceptable thresholds for protein, bilirubin, and lipids. We verified a reference range of 33.1-60 â€‹µg/g in our patient population. Deming regression identified acceptable correlation with minor positive bias (2.7%) between the fCal Turbo and fCal ELISA methods. CONCLUSIONS: The fCal Turbo assay performs well on the Vitros 5600 analyzer in our patient population, with the assay being easy to use in our routine chemistry workflow. We anticipate that the fCal Turbo assay will be useful as a rapid screening method for differential diagnostics and disease monitoring of IBD in our patient population.

Clinical Validation and Performance Evaluation of the Automated Vitros Total Anti-SARS-CoV-2 Antibodies Assay for Screening of Serostatus in COVID-19.

OBJECTIVES: Evaluation of serostatus against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as an important tool in identification of exposure to coronavirus disease 2019 (COVID-19). We report on the validation of the Vitros Anti-SARS-CoV-2 Total (CoV2T) assay for qualitative serologic testing of SARS-CoV-2 antibodies. METHODS: We performed validation studies according to Commission of Office Laboratories Accreditation guidelines, using samples previously tested for SARS-CoV-2 by reverse transcription-polymerase chain reaction (RT-PCR). We evaluated precision, analytical interferences, and cross-reactivity with other viral infections; evaluated concordance with molecular and other serologic testing; and evaluated seroconversion. RESULTS: The Vitros CoV2T assay exhibited acceptable precision and did not exhibit cross-reactivity with other acute respiratory virus infections. The CoV2T assay exhibited 100% negative predictive agreement (56/56) and 71% positive predictive agreement (56/79) with RT-PCR across all patient samples and was concordant with other serologic assays. Concordance with RT-PCR was 97% more than 7 days after symptom onset. The CoV2T assay was robust to icterus and lipemia but had interference from significant hemolysis. CONCLUSIONS: The Vitros CoV2T assay was successfully validated in our laboratory. We anticipate it will be a useful tool in screening for exposure to SARS-CoV-2; however, the use of the CoV2T and other serologic assays in the clinical management of patients with COVID-19 is unknown and must be evaluated in future studies.

Efficacy of two vitamin D immunoassays to detect 25-OH vitamin D2 and D3.

OBJECTIVES: Assessment of Vitamin D status by measurement of 25-Hydroxyvitamin D (25-OH-D) is widely performed by immunoassay. Yet, the ability of these assays to detect Vitamin D2 (as 25-OH-D2) or Vitamin D3 (as 25-OH-D3) varies. It is important to recognize the ability of an assay to quantitate either form of 25-OH-D to evaluate Vitamin D status of supplemented patients. We evaluated detection of 25-OH-D2 and 25-OH-D3 by two assays in our medical center. DESIGN AND METHODS: The Abbott Architect i1000 SR 25-OH Vitamin D assay and Roche Cobas 8000 Vitamin D assay were compared for their recovery of 25-OH-D2 or D3 from spiked serum samples. Samples with known endogenous concentrations of 25-OH-D2 or D3 by LC-MS/MS were also measured to calculate bias between our assays and LC-MS/MS. RESULTS: Recovery of 25-OH-D3 in spiked samples was similar by Architect (84-87%) and Cobas (90%). Recovery of 25-OH-D2 was lower than 25-OH-D3, and was poorer by Architect (37-40%) than by Cobas (69-71%). In measurement of samples with known 25-OH-D concentrations, performance of Architect and Cobas assays was similar for 25-OH-D3. However, at concentrations >50 nmol/L 25-OH-D2, the Architect assay exhibited large average negative bias (-27%). CONCLUSIONS: While the Architect and Cobas assays performed similarly in detection of 25-OH-D3, the Architect assay was significantly poorer at detecting 25-OH-D2 than Cobas, with poorer recovery and significant negative bias at higher concentrations of 25-OH-D2. This agrees with other studies, and indicates that caution should be used in interpreting Architect 25-OH-D results in patients supplemented with Vitamin D2.

Discordant Analytical Results Caused by Biotin Interference on Diagnostic Immunoassays in a Pediatric Hospital.

Recent studies have reported that biotin interferes with certain immunoassays. In this study, we evaluated the analytical interference of biotin on immunoassays that use streptavidin-biotin in our pediatric hospital. We tested the effect of different concentrations of biotin (1.5-200 ng/ml) on TSH, Prolactin, Ferritin, CK-MB, ß-hCG, Troponin I, LH, FSH, Cortisol, Anti-HAV antibody (IgG and IgM), assays on Ortho Clinical Diagnostic Vitros 5600 Analyzer. Biotin (up to 200 ng/mL) did not significantly affect Troponin I and HAV assays. Biotin (up to 12.5 ng/ml) resulted in <10% bias in CK-MB, ß-hCG, AFP, Cortisol, Ferritin assays and biotin >6.25 ng/mL significantly affected TSH (>20% bias) assay. Prolactin was significantly affected even at low levels (Biotin 1.5 ng/mL). Thus, we recommend educating physicians about biotin interference in common immunoassays and adding an electronic disclaimer.