Insignificant interference of Elevit in pregnant women serum samples with HBsAg immunoassay on Sysmex

Determination of potential biotin interference on accuracy of results of serologic assays for various viral hepatitis markers

Biotin taken orally can interfere with some diagnostic immunoassays, including those for thyroid hormones, ferritin, and markers of infectious disease. Assays affected are ones that use streptavidin-biotin in their design. The goal of our study was to examine the effect of biotin concentrations of up to 1200 ng/mL on three serological assays performed on VITROS 3600 system, Immunoglobulin M (IgM) antibodies to hepatitis A virus (anti-HAV), total anti-HAV, and IgM antibodies to hepatitis B virus core antigen (anti-HBc), by spiking serum samples with variable amounts of biotin. No false-negative results were generated with either concentration of biotin for total anti-HAV (65/65). Likewise, biotin caused no false-positive IgM anti-HAV results (59/59) with either concentration of biotin; however, 6.7% false negativity was found for IgM anti-HAV when samples were spiked with 1200 ng/mL of biotin. Conversely, 100% false positivity (30/30) was produced by biotin interference in total anti-HAV negative specimens with both concentrations of biotin. False negativity rate was 87.5% in IgM anti-HBc positive samples when biotin levels were at 1200 ng/mL. These data show that individuals taking biotin-containing supplements may test false-positive in some serologic assays using streptavidin-biotin chemistries. Further studies are warranted to determine the extent of biotin interference resulting in false-positive and negative results and their impact, if any, on surveillance and diagnostic settings.

Prevalence of anemia and iron deficiency anemia in Chinese pregnant women (IRON WOMEN): a national cross-sectional survey

Background

The current evidence about anemia and iron deficiency anemia (IDA) during pregnancy remains elusive in China. The purpose of this study is to investigate the prevalence of anemia and IDA and their risk factors in Chinese pregnant women.

Methods

A nationwide cross-sectional survey of pregnant women was conducted during their antenatal visits. Using a multi-stage sampling method, 24 hospitals from 16 provinces across China were selected. Structured questionnaires were administered to collect information from participants and to extract clinical data from electronic medical records. Mixed-effects logistic regression models were performed to determine the risk factors associated with anemia and IDA.

Results

In total, 12,403 pregnant women were enrolled, including 1018 (8.2%) at the first trimester, 3487 (28.1%) at the second, and 7898 (63.7%) at the third. Overall, 19.8% of women were diagnosed with anemia and 13.9% were diagnosed with IDA. The prevalence of anemia and IDA varied among regions and increased by gestational month, peaking at the eighth gestational month (24.0% for anemia and 17.8% for IDA). Pregnant women at advanced stage of gestation, non-local residents, multiple gestations, multiparity, pre-pregnancy underweight, and those experiencing severe nausea or vomiting during pregnancy, were associated with higher risks of anemia and IDA.

Conclusions

The prevalence of anemia and IDA during pregnancy are similar to those from developed countries and vary across regions in China.

Biotin interferences: Have we neglected the impact on serological markers?

BACKGROUND

Biotin has been reported to be a leading cause of interference on several immunoassay platforms using the streptavidin-biotin immobilization system. While biotin interferences have now been well characterized for several assays, only few data are available on their impact on serological markers of infectious viral diseases.

METHODS

Overall, 10 healthy volunteers (HVs) received a single 100 mg dose of biotin to evaluate its effect on hepatitis B serological markers. Blood samples were taken several times before and after biotin intake. In addition, spiking experiments were applied to investigate biotin's impact on anti-HIV/p24 Ag and anti-HCV antibody levels. Several procedures designed to overcome this interference were evaluated.

RESULTS

Biotin intake resulted in a false-negative anti-HBs immunological status (<10 mIU/mL) in 40.0% of cases. According to our anti-HBc and anti-HBe results, biotin intake was associated with 90.0% and 80.0% of false positive results, respectively. At the theoretical biotin peak concentration following a 100 mg intake, 50.0% and 66.6% of anti-HIV and anti-HCV results were false negatives, respectively. All the procedures evaluated to overcome the interference were proven effective.

CONCLUSION

HBV, HCV, and HIV serological markers are likely to be highly sensitive to biotin. Our data confirm that the scope of biotin interference is broader than commonly described.

Insignificant interference of Elevit in pregnant women serum samples with HBsAg immunoassay on Sysmex

BACKGROUND

The pregnant women often take Elevit as the multivitamin supplement which has a substantial amount of biotin that might potentially interfere with the HBsAg immunoassay performed by the prevalent Sysmex system in clinical laboratories. We therefore wanted to determine this, so that the therapeutic intervention on the hepatitis B virus infection during pregnancy and birth would not be missed.

METHODS

Elevit was both serially diluted in vitro and orally taken by healthy volunteers whose blood samples were then taken at different time points. All samples were added to a serum sample with a known result of HBsAg and then measured by Sysmex. The Abbott immunoassay system was used as the control as it involves no streptavidin-biotin binding in the reagent set. Besides, the HBsAg results were compared between the pregnant women taking or not taking Elevit.

RESULTS

Biotin at 25 ng/mL in the Elevit started to suppress the HBsAg and reached about 50% suppression at 100 ng/mL on Sysmex. In the volunteers, biotin reached the peak concentration at 2 hours. However, their blood samples showed no suppression on the HBsAg detection by Sysmex. In samples from pregnant women who took Elevit, the HBsAg results by Sysmex were highly correlated with those by Abbott (R²  = 0.96). Comparison of the results from Sysmex between the age- and pregnancy-matched females with and without Elevit intake showed no difference.

CONCLUSION

Elevit intake in pregnant women shows no significant interference with HBsAg immunoassay on Sysmex.