Assessment of former and newly developed HBV assays in a Third World setting

Newly available HBV serological assays have not been established routinely in most underdeveloped countries. Utilizing enzyme-immune assays to determine the presence of pre-S1 antigen and anti-pre-S2, and using two conventional hybridization techniques and the PCR assay to detect HBV-DNA, we studied 30 HBsAg chronic carriers and as a reference group 10 subjects whose only HBV routine marker was anti-HBc. Seventy-nine percent of the HBeAg positive carriers showed detectable HBV-DNA by a non-radioactive slot-blotting technique. The PCR assay was more sensitive than the slot-blotting technique, detecting HBV-DNA in anti-HBe positive patients with moderate or normal ALT activity. Pre-S1 antigen was mostly related to the presence of HBsAg and anti-pre-S2 was associated with active viremic state, increased ALT activity (ranges 51 to 640 IU/L), and with self-limited HBV infection. The presence of HBV-DNA in the group with anti-HBc only was detectable solely by the PCR assay. For an underdeveloped country the addition of a PCR assay or pre-S/anti-pre-S protein tests to the current assessment procedures of HBV chronic infection should be used only in selective cases. HBeAg/anti-HBe serological evaluation and HBV-DNA detection by a non-isotopic conventional hybridization technique still remain as useful tools to screen initially for the presence of viremia in chronic HBsAg carriers. The presence of HBV-DNA in individuals with anti-HBc only suggests that anti-HBc screening should be maintained and expanded to all the blood banks of less industrialized countries where the rate of HBV infection in apparently healthy people tends to be high.