[A retrospective study of HBsAG carriers in the blood bank of Navarra].

The following is a review of the data of hepatitis-B serology study obtained during the last sixteen years in the Blood Bank of Navarra. The prevalence of HBsAg carriers is 0.87% (204 positive cases in 23,409 blood donors studied). The methods used during this period have been: AGD (7 positive donors, i.e. 3.4%), CIEP (4 positive donors, i.e. 1.9%), HARP (78 positive donors, i.e. 38.2%), EIA (93 positive donors, i.e. 45.5%) and RIA (22 positive donors, i.e. 10.7%). The number of previous donations before the detection of HBsAg dropped from 7/8 in the first group of donors to 4/5 in the second and to 1 in the third group. A deeper study has been carried out in 120 of those blood donors, including the detection of anti-HBs, anti-HBc, HBeAg and anti-HBe. A low-infectivity pattern has been found in 92 (76.6%), high infectivity in 4 (3.3%) and seroconversion in 16 (13.3%). It hasn't been possible to interpret the pattern of the remaining 8 (6.6%). Both the sensitivity and the specificity of our actual screening method have been found adequate in a cooperative study carried out in a group of Blood Banks in Spain in 1985.