[Clinical diagnosis of thrombosis and blood coagulation tests]

Abstract

Blood coagulation tests are useful to diagnose some thrombotic diseases. Particularly, these tests are valuable for the diagnosis of familiar thrombophilia, antiphospholipid antibody syndrome (APS) and disseminated intravascular coagulation (DIC). For the diagnosis of thrombophilia, determinations of both biological activity and antigen level of antithrombin III, protein C and protein S are important for initial screening. Since activated protein C (APC) resistance is extremely rare in Japanese, APC resistant test that based on APTT, is unnecessary to include as one of the screening tests. Detection of activity and antigen level of either plasminogen or fibrinogen is recommended to screen the plasminogen deficiency or dysfibrinogenemia. Determination of lupus anticoagulant is needed for the diagnosis of APS. At this time, the dilute phospholipid APTT (dAPTT) or the dilute Russell viper venom time (dRVVT) may be useful as a screening test for LA because procedure of these tests are basically simple to perform in Japanese laboratory. In the next step, cross mixing test of dAPTT (or APTT) should be perform to make a diagnose of LA more solid. Final confirm tests can be conveniently carried out with kit of either STACLOT or LA-CONFIRM. Platelet count and FDP (or FDP D dimer) assay are two essential tests for the diagnosis of DIC. Criteria of diagnosis for DIC recommended by Blood Coagulation Research Group of Japanese Ministry of Health and Welfare is not unnecessarily appropriate for practical use. TAT and PIC can be a good laboratory tests for early detection of hypercoagulable state in patients with DIC.