Laboratory Tests in Bleeding Disorders
Bleeding disorders are the result of a generalized defect in hemostasis due to abnormalities of blood vessels, platelets, or coagulation factors.
Initial tests, which should be performed in a suspected bleeding disorder, are complete blood count including blood smear, platelet count, bleeding time, clotting time, prothrombin time, and activated partial thromboplastin time. Depending on the results of these screening tests, one or more specific tests are carried out for definitive diagnosis (e.g. platelet function studies, assays of
coagulation factors, and test for fibrin degradation products). Abnormalities of blood vessels are usually not detectable by laboratory tests for hemostasis, and their diagnosis requires correlation of clinical and other investigations.
A complete blood count and a blood smear can provide information in the form of:
• Presence of cytopenia (anemia, leukopenia, thrombocytopenia)
• Red cell abnormalities (especially fragmented red cells which may indicate disseminated intravascular
• White cell abnormalities (like abnormal cells in leukemias)
• Abnormalities of platelets: thrombocytopenia (normally there is 1 platelets per 500-1000 red cells), giant platelets (seen in myeloproliferative disorders and Bernard-Soulier syndrome), and isolated discrete platelets without clumping in finger-prick smear (seen in uremia, Glanzmann’s thrombasthenia).
(2) Platelet Count
(3) Bleeding Time (BT)
(4) Clotting Time (CT)
(5) Prothrombin Time (PT)
(6) Activated Partial Thromboplastin Time (APTT)
(7) Thrombin Time (TT)
(8) Platelet Function Analyzer-100
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- Posted by Dayyal Dg.