Detection of serum fibrinogen and fibrin degradation products: Comparison of six technics using purified products and application in clinical studies

Abstract

Six assay systems for serum fibrin degradation products (tanned red cell hemagglutination inhibition immunoassay (TRCHII), staphylococcal clumping test, Fi test, flocculation, immunodiffusion and anticoagulant assay) were compared for reactivity with plasmin digests of fibrinogen and fibrin, with purified degradation products and with serum obtained from patients suspected of having circulating degradation products. The TRCHII reacts best with undigested fibrinogen and with the intermediate degradation fragments X and Y. Although less reactive with purified fragments, the staphylococcal clumping test is as reliable for the assay of test serums, and both react with about 90 per cent of test serums. This suggests that circulating complexes of degradation products with fibrin monomer or with fragment X may be responsible for the positive results of test serums. One patient with defibrination syndrome and one with therapeutic thrombolysis were studied in detail with respect to the usefulness of the six assay systems in reflecting the presence of a hemorrhagic diathesis. The flocculation test is probably of the greatest value for emergency clinical situations, as it is rapid and simple, yet consistently sensitive to levels of degradation products that cause abnormal bleeding.