Comparison And Clinical Significance Of Detection For Quantitative Of Hepatitis B Surface Antigen In Different Dilution Methods

Background and Objective Chronic hepatitis b (CHB) is a serious disease to threaten the health of human. Hepatitis b surface antigen (HBsAg), the embrane protein of hepatitis b virus (HBV) which coded by S genetic of virus plays an important role in the process of infecting liver cells. Recent research shows that serum HBsAg level is not only reflect HBV replication level to a certain extent, more important it has certain correlation with covalently closed circular DNA (cccDNA), which is the replication template of HBV in liver cells. With the research and development of anti-viral drugs and improving of treatment methods, the detection of HBsAg quantitative attracts more and more attention of researchers and clinicians, especially the early serum HBsAg drop has predictive value to the ongoing sustained virological response (SVR). Detection of HBsAg quantitative accurately has important significance in judging if infect or clear HBV and guiding antiviral treatment. Resently, HBsAg quantitative kit (ARCHITECT(?) HBsAg) produced by Abbott is only approved by the U. S. Food and Drug Administration (FDA). The linear range detected by Architect HBsAg quantitative is 0-250IU/mL, there are few studies on accurate detection about quantitative of HBsAg which are over than the maximum linear range, the main reason is exclusive ancillary dilutions expensive thus limiting its clinical application. In the study, normal saline was used to dilute samples for them over than the linear range, then tested and compared with that diluted by special supporting dilution to analyze the consistency of different quantitative results, and also studied preliminarily the association between HBsAg quantitative and clinical indicators.Materials and Methods:96 cases were selected from the outpatient and inpatient with chronic HBV infection, Architect HBsAg quantitative of patients were all over than 250IU/mL, and ruled out hepatitis A, hepatitis C,. hepatitis E virus infection, Diagnosis accord to the diagnostic criteria of guideline on prevention and treatment of chronic hepatitis B in China (2005). All the specimens were respectively diluted in matching standard dilution (Method A), physiological saline (Method B) according to the instructions, physiological saline but one-step dilution (Method C), and then tested. There were respectively 4 cases and 5 cases who can not get concrete determination value diluted according to Method A and B (> 125000U/mL).91 cases that all had concrete determination value diluted according to three dilution method were chosen into statistical analysis to compare the consistency of HBsAg quantitative. HBsAg quantitative diluted by Method A as the standard,44 cases who had not received any antiviral treatment were selected. The correlation were respectively analyzed between HBsAg quantitative and disease status, HBeAg status, HBeAg level, HBV DNA level, gender, age, ALT. Results l.The logarithmic range of determination value were respectively (2.72～4.92) log10IU/mL, (2.52～4.97) log10IU/mL, (2.54～4.84) log10IU/mL in Method A, Method B and Method C, medians were respectively 3.83 log10 IU/mL,3.81 log10 IU/mL and 3.54 log10IU/mL. Difference of testing results between Method B and Method A was not statistically significant (P= 0.712), while difference of testing results between Method C and A was statistically significant (P=0.000). There were good correlation between Method B and Method A, between Method C and Method A(r=0.919 0.969, P=0.000). Adopt Bland-Altman method analysis, in 95% of consistency boundary, most differences were located within the region. In different MBsAg horizontal, Method B and C had good correlation with Method A.2. HBsAg quantitative of Chronic hepatitis b group was higher than that of cirrhosis group (P=0.001), HBsAg quantitative of HBeAg-positive group was higher than that of HBeAg-negative group (P=0.001), differentce of HBsAg quantitative between genders had no statistically significant (P=0.448). In HBeAg-positive group, Levels between HBsAg quantitative and HBeAg were positively correlated (r=0.675, P=0.000), in HBV DNA positive group, levels of HBsAg quantitative and HBV DNA were positively correlated (r=0.613, P=0.000). HBsAg quantitative had no correlation to age (r=-0.291,P=0.055) and ALT (r=0.162, P=0.306). CONCLUSIONS The results tested by Method B and Method A showed good agreement. HBsAg quantitative can reflect the level of HBV replication to a certain extent.