This paper described a direct spot hybridization test using 5-10ul sera sample and various factors related its sensitivity and specificity were discussioned. The procedure is as follow: 1) spoting sample on the smaller diameter hole of filtration appartus under lower vaccum

2) denaturating sample befor spoting

baking filter paper membrance more than 2 hours at 80C; 3) 32p-HBVDNA amount more than 7x105cpm/100 sample

hy-bridizating with probe at more than 18 hours and autoradiography 2-4 days. Its sensitivity was 0.1 pg. 322 serum samples of patients and donors were determined

116 of 322 samples showed HBV DNA positive. 80 of 90 HBsAg and HBeAg positive serum samples were HBV DNA positive (88.9%) and 28 of 159 anti-HBe positive samples HBV-DNA posi-tive(l7.6%) and 8 of 73 both HBeAg and anti-HBe negative samples HBVDNA positive (11.0%

p<0.005

HBeAg (+) vs. anti-HBe (+) and both (-)). We inclined to think this was a sensitive

specific and simple method for clinical and laboratory studies