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PubMed · 3010489

A simplified PTT-based protein C activity assay using the thrombin-thrombomodulin complex.

R B Francis
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Abstract

A simplified assay for protein C activity in plasma is described which uses the ability of rabbit lung thrombomodulin to inhibit the procoagulant activity of thrombin while stimulating protein C activation. Barium eluates of plasma are activated for one hour at 37 degrees C by a mixture of human thrombin and rabbit lung thrombomodulin at concentrations which neutralize each other's effect on the kaolin-cephalin activated partial thromboplastin time (PTT). Protein C anticoagulant activity in the activated eluates is then measured directly in the PTT. The method is independent of protein S levels in the test samples, and is suitable for warfarinized and heparinized plasma. Protein C levels obtained with this method correlate closely with functional levels of vitamin K-dependent procoagulants as measured by the prothrombin and proconvertin time (P&P) in normal subjects and in patients receiving warfarin, indicating specificity for gamma-carboxylated protein C. The method has the potential to detect molecular variants defective in any of the interactions required for generation of anticoagulant activity in vivo.

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Blood Coagulation TestsGlycoproteinsHumansMethodsPartial Thromboplastin TimeProtein CReceptors, Cell SurfaceReceptors, ThrombinThrombinWarfarinJournal Article

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R B Francis. 1986-02-01. A simplified PTT-based protein C activity assay using the thrombin-thrombomodulin complex.. https://doi.org/10.1016/0049-3848(86)90244-6

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