Accidental transfusion of blood containing HBsAg or anti-HBs.

The presence of HBsAg and anti-HBs was tested in 2,099 surgery patients and in the blood left in 3,157 flasks after transfusion. It was found that accidental transfusion of HBsAg-containing blood had occurred. The 30 patients in which seropositivity correlations between recipients and transfused blood could be established were followed up clinically and serologically at 3, 6 and 12 months after transfusion. Out of the 13 initially seropositive patients 5 showed clinical or subclinical symptoms of viral hepatitis (V.H.). Most of the recipients of HBsAg-containing blood developed a biological response consisting in the appearance of either V.H. or anti-HBs. An increased number of fatal cases was recorded among recipients of anti-HBs-containing blood within 1 to 16 days post transfusion.