Comparisons Of Two Enzyme Immunoassay Kits For Total Antibody To Hepatitis A Virus Detection And Primarily Application

Hepatitis A virus (HAV) infection is a common health issue throughoutt the world. The level of sanitation or hygiene in the environment markedly influences the epidemiology of hepatitis A. The principal mode of transmission for HAV is by the fecal-oral route, often resulting in community-wide outbreaks. The total antibody to HAV (anti-HAV) is an important marker for HAV seroepidemiology, which can indicate a history of HAV infection or immunization. In order to strengthen the quality control in laboratory detection and provide a reference to assay selection for seroepidemiology in HAV, we evaluated several enzyme immunoassays kits that detect antibody to HAV and then primarily applied in seroepidemiology.Through fitting the standard curves and selecting a best one. we established the quantitative method for total anti-HAV. The standard reference serum of known concentration was serially diluted to13concentrations, then each of them was examined5times by HAVAb2.0kit produced by Abbott Laboratories and got CO/S values. Three mathematical models and two data transformations were used to fitting6kinds of standard curves at the same range. Accuracy and error for each function were measured and compared. Each function achieved a high squared correlation indicating a high degree of accuracy in forming the standard curves. However, logistic models got the highest R2and when predicted antibody concentrations were compared with the known values, the logistic models exhibited the most precision. However, no differences between two transmations (including natural logarithm and logarithm to base10) at accuracy in forming the standard curves was observed.We established a total anti-HAV panel to compare different assays. Under the premise of eligible quality control, we examined314blood serum specimens and detected the specimens in gray area3times. The serums that had3positive or negative results were enrolled in the panel and others were excluded. Then, according to the quantitative results, excluded some serum with high concentrations, whilediluted6serums at300-500mIU/ml to increase the number of weak reactive samples. Finally, the total anti-HAV panel we established had71positive serums including12serums which concentrations>10OOOmIU/ml,11serums which concentration were1000-10OOOmlU/ml,37serums at100-<1000mIU/ml,11serums concentration<100mIU/ml and64serums negative. Diluted serums had17serums at100-500mIU/ml.18serums at<100mIU/ml and7negative serums.Two China-made enzyme immunoassays kits that detect total antibody to hepatitis A virus (Anti-HAV) are evaluated for their performance. Each of the two kits was tested8times with the total Anti-HAV antibody panel. The CO/S ratios were recorded and transformed by ln(CO/S+0.1), and the generalized estimating equation (GEE) model was applied to predict the positive probabilities on their gold standard outcomes. The Intraclass correlation coefficient (ICC) were0.9971and0.9952for assay A and B(Bootstrap method, P<0.05), respectively. The coefficient of variability (CV) were5.7840%and6.2931%for assay A and B(Bootstrap method, P<0.05) respectively. Similarly, area under curve (AUC) and partial area under curve (pAUC). Sensitivity at a Fixed Specificity [Se(FPR=e)](specificity ranging from0.9to1) were0.9557and0.0717for assay A, and0.9404and0.0663for assay B, respectively. When Se(FPR=0.020) to Se(FPR=0.070) were calculated at0.005intervals, higher sensitivities can be observed in assay A (Bootstrap method, P<0.05) if the specificities were0.945、0.950、0.955or0.960; but at other points of the specificities, there were not (Bootstrap method, P>0.05). Then transformed CO/S value to binary variable.When CO/S≥1, it is positive, when<1, negative. Then calculated and got crude accuracy(CA) for assay A and B were92.66%and90.40%, respectively. Kappa value were0.85and0.80for two assays respectively. Sensitivity and specificity for assay A were94.34%and90.14%, for assay B were88.68%and92.96%. Youden’s index were0.84and0.81. However, there were no statistically significance. In conclusion, both assays are excellent. Although there are statistical differences in some indices, practical differences are still unknown. So, according to the specific situation, decide which assay to use in practical application.In the cross-sectional study as the primarily application to comparison of assays, we investigated the seroprevalence of HAV among adolescents in Inner Mongolia.587subjects were enrolled in this study, and we found an overall seroprevalence of14.31%in our population which is relatively low. There were statistical differences within different age groups (logistic regression.P<0.05). The study findings indicate that vaccination against HAV will be beneficial.