Screening Laboratory Test Results and Treatment of Inherited Blood Coagulation Defects
Screening Test Results* | Defect | Comments |
|---|---|---|
PTT long PT normal | Factor XII, high molecular weight kininogen, or prekallikrein | Laboratory test abnormality without clinical bleeding Specific assays required to distinguish from factor XI deficiency, in which posttraumatic and perioperative bleeding may occur No treatment required |
PTT long PT normal | Factor XI | Autosomal recessive Increased frequency in patients of Ashkenazi Jewish ancestry Posttraumatic and perioperative bleeding Diagnosis by specific factor assay For treatment of bleeding: plasma-derived factor XI concentrate or fresh frozen plasma, plus inhibition of fibrinolysis by aminocaproic acid or tranexamic acidFor treatment of bleeding: plasma-derived factor XI concentrate or fresh frozen plasma, plus inhibition of fibrinolysis by aminocaproic acid or tranexamic acid Plasma factor XI half-life = 50 hours |
PTT long PT normal | Factor VIII or IX | Factor VIII deficiency (hemophilia A) Factor IX deficiency (hemophilia B) X-linked transmission Mild or severe bleeding in males, depending on factor VIII or factor IX level For treatment of bleeding: factor replacement Plasma factor VIII half-life = 8–12 hours Plasma factor IX half-life = 18 hours |
PTT normal PT long | Factor VII | Autosomal recessive, rare Diagnosed by specific factor assay For treatment of bleeding: Recombinant activated factor VII or plasma-derived factor VII concentrate Plasma factor VII half-life = 4–6 hours |
PTT long PT long | Factor X, V, or prothrombin | Autosomal recessive, rare Mild to severe bleeding Diagnosed by specific assays For treatment of bleeding due to factor X or prothrombin deficiency:
For treatment of bleeding due to factor V deficiency: Fresh frozen plasma with or without platelet concentrates (to supply platelet factor V) Plasma half-life of factor X = 40–60 hours Plasma half-life of prothrombin = 60–72 hours Plasma half-life of factor V = 36 hours |
In afibrinogenemia (fibrinogen < 10 mg/dL [< 0.1 g/L]), no clotting in PTT or PT because machine end point is not triggered In hypofibrinogenemia (fibrinogen 70–100 mg/dL [0.7–1 g/L]), PTT and PT often prolonged by several seconds and thrombin time longIn hypofibrinogenemia (fibrinogen 70–100 mg/dL [0.7–1 g/L]), PTT and PT often prolonged by several seconds and thrombin time long | Fibrinogen | Severe bleeding in afibrinogenemia (homozygous state) Posttraumatic and perioperative bleeding in hypofibrinogenemia (heterozygous state) For treatment of bleeding:
Plasma half-life of fibrinogen = 2–4 days |
PTT and PT long Thrombin time longThrombin time long | Dysfibrinogenemia | Various manifestations (no, or only mild, posttraumatic and perioperative bleeding, tendency for thrombosis, wound dehiscence) Fibrinogen low in clotting assay but normal in immunologic assay |
PTT normal PT normal Thrombin time normalThrombin time normal Clot lysis in 5M ureaClot lysis in 5M urea | Factor XIII | Autosomal recessive, rare Poor wound healing For treatment of bleeding:
Plasma half-life of factor XIII = 9–12 days |
PTT and PT normal Clot lysis times in 5M urea or saline acceleratedClot lysis times in 5M urea or saline accelerated | Alpha 2-antiplasmin deficiency | Severe bleeding in homozygotes Posttraumatic and perioperative bleeding in heterozygotes Specific assay required for confirmation of diagnosis For treatment of bleeding: Inhibition of excessive fibrinolysis using aminocaproic acid or tranexamic acidFor treatment of bleeding: Inhibition of excessive fibrinolysis using aminocaproic acid or tranexamic acid |
* PT results are typically reported as INR. | ||
PT = prothrombin time; PTT = partial thromboplastin time. | ||