RESUMEN
Of 559 HBsAg-negative healthy patients,the positive rate of testing for antibody to both HBc and HBs was 31.31% (176/559),and the po- sitive rate of testing for antibody only to HBc was 26.83% (150/559).Of 150 random-sampled blood specimens with positive antibody only to HBc and 150 random-sampled blood specimens with positive antibody to both HBs and HBc,the positive rates of testing for HBVDNA,using the dot hybridi- zation technique,were 5.33% and 2.0% respectively.The positive rate of testing for HBVDAN in high titer blood with positive antibody only to HBc was higher(12.0%) than that (4.0%) in low titer blood with posi- tive antibody only to HBc.The results of testing showed that the HBsAg- negative blood could still take the risk of transmitting HBV,the blood with positive antibody to both HBs and HBc was not absolutely safe,the HBV- transmitting risk of high titer blood with positive antibody only to HBc was even higher.Additional testing the donors for antibody to HBc should be recommended.