[Fibrinogen estimation. A simplified gravimetric method (author's transl)].

Abstract

UNLABELLED: A simplified gravimetric method is proposed for fibrinogen estimation in plasma. Technic: 0.5 ml plasma (citrated) are diluted to up 5 ml with saline. A stick, 5 to 6 cm long, made of a glass capillary tube, or, aluminium foil, with ends bended as a hock, are weighted up to 0.001 g. Introduce one stick previously weighted in diluted plasma. Place two drops of thrombin (10 U/ml), and mix. In seconds, all fibrinogen is transformed in fibrin, deposited around the stick. Remove the stick with the fibrin, and press gently with the fingers, expelling the liquid in excess. Hang the stick with the fibrin, on the rim of a dry centrifuge tube. Centrifuge at 3.000 rpm for 10 minutes (dry centrifugation). Centrifugal forces acting on the fibrin clot expell all liquid particles. Fibrin consist of a very thin layer adhered on the stick. The weight difference (initial and final), represents the solid fibrin. CALCULATION: difference of weight added by 0.1 of the difference (anticoagulant dilution) x 200 to convert in dl. The method is highly reproductible, and takes about 20 minutes to be completed.