Plasma Glycated Albumin in Early Pregnancy and Gestational Diabetes Mellitus: A Prospective and Longitudinal Study.

OBJECTIVE: To investigate associations of plasma glycated albumin (GA) concentrations in early and midpregnancy with gestational diabetes mellitus (GDM) risk. RESEARCH DESIGN AND METHODS: We measured GA concentrations using blood samples collected at 10-14 and 15-26 weeks' gestation (GW) in 107 GDM case subjects and 214 control subjects from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Fetal Growth Study. We performed generalized linear mixed-effect regression to test the mean GA difference between GDM case subjects and control subjects and conditional logistic regression to assess prospective associations between GA concentrations and GDM risk. RESULTS: At 15-26 GW, mean GA was lower in GDM case subjects than control subjects (mean 11.90% [95% CI 6.42-32.76] vs. 12.46% [8.45-38.35], adjusted P value for difference = 0.004). Consistently, women with higher GA concentrations tended to have a lower GDM risk, although the associations were not statistically significant. CONCLUSIONS: This study suggests that GA concentrations in midpregnancy might be lower in women who later develop GDM. Further studies are needed to identify the mechanism.

A Longitudinal Study of Plasma Glycated Albumin across Pregnancy and Associations with Maternal Characteristics and Cardiometabolic Biomarkers.

BACKGROUND: Glycated albumin (GA) has recently been proposed as a screening marker for diabetes among non-pregnant individuals. However, data on GA during pregnancy are sparse and lacking among women of diverse race/ethnicity. We investigated longitudinal concentrations of GA among multiracial pregnant women in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons. METHODS: We quantified GA and cardiometabolic biomarkers using longitudinal plasma samples collected at 10 to 14, 15 to 26 (fasting), 23 to 31, and 33 to 39 gestational weeks from 214 pregnant women without gestational diabetes. We examined the distribution of GA across pregnancy and its association with participants' characteristics including race/ethnicity, pre-pregnancy body mass index (ppBMI), and selected cardiometabolic biomarkers. GA trajectories were estimated using a latent class approach. RESULTS: Medians (interquartile range) of GA concentrations were 12.1% (10.6%-13.4%), 12.5% (10.7%-13.8%), 12.4% (10.9%-13.5%), and 11.5% (10.4%-12.5%) at 10 to 14, 15 to 26, 23 to 31, and 33 to 39 weeks, respectively. There were no significant differences in the pattern among different race/ethnic groups (P > 0.53). A minority of women exhibited a GA trajectory characterized by a high concentration of GA at 15 to 26 weeks. GA concentrations were inversely related to ppBMI and plasma low-density lipoprotein and triglyceride concentrations, but were not significantly related to hemoglobin A1c, fasting insulin, or glucose over pregnancy. CONCLUSIONS: In this study of individuals who were normoglycemic before pregnancy, plasma GA concentrations stayed relatively constant over pregnancy, decreasing only in late pregnancy. GA concentrations were inversely related to ppBMI and suboptimal lipid profiles, but did not appear to be a sensitive marker for glucose metabolism in pregnancy.

Evaluation of the Ortho-Clinical Diagnostics Vitros ECi Anti-HCV test: comparison with three other methods.

After observing a high incidence of low positive hepatitis C virus (HCV) antibody screens by the Ortho-Clinical Vitros ECi test (Orthoclinical Diagnostics, Raritan, NJ), we compared results against those obtained using another chemiluminescent analyzer, as well as two U.S. Food and Drug Administration (FDA)-approved confirmatory methodologies. To ascertain the true anti-HCV status of samples deemed low-positive by the Ortho-Clinical Vitros ECi test, we tested samples using the ADVIA Centaur HCV screen test (Siemens Medical Solutions Diagnostics), the Chiron recombinant immunoblot assay (RIBA) test (Chiron Corp., Emeryville, CA), and the Roche COBAS Amplicor HCV qualitative test (Roche Diagnostics, Indianapolis, IN) in a series of studies. Of 94 specimens positive by Vitros ECi, 19% were observed to be negative by Centaur. A separate study of 91 samples with signal-to-cutoff (s/co) values less than 8.0 showed that all but one was negative for HCV ribonucleic acid (RNA). In comparison with RIBA, 100% (77) samples positive by the Vitros ECi test with s/co values less than 12.0 were negative or indeterminate by RIBA. A final study comparing all four methods side-by-side showed 63% disagreement by Centaur for Vitros ECi low-positive samples, 75% disagreement by RIBA, and 97% disagreement by polymerase chain reaction (PCR). In conclusion, the Ortho-Clinical Vitros ECi Anti-HCV test yields a high rate of false-positive results in the low s/co range in our patient population.