| Abstract: | During a period when screening for hepatitis B surface antigen (HBsAg) was performed by immunodiffusion using dextran-containing agarose gel, a diffuse precipitation (DP) zone was observed when citrate plasma samples were reacted with certain serum specimens. The DP reaction was noted with a significantly larger number of sera from patients with renal disorders, hepatitis, or certain other virus infections than with sera from apparently healthy blood donors, indicating that it was associated with some type of pathological condition. Highly purified fibrinogen used as detector reagent instead of plasma was sufficient to elicit a precipitation zone similar to that of the DP reaction. In the presence of coagulation inhibitors such as heparin, hirudin and antithrombin III the DP reaction was inhibited, suggesting that the precipitation zone represents coagulation. Cross-linked fibrin was demonstrated in the precipitates of DP-positive sera but not in the corresponding zone of a DP-negative serum. |
