Interpretation of results: The platelet count indicates that the patient has a normal amount of platelets. The bleeding time assesses platelet function. Although the patient's bleeding time is on the long side, it is still within normal range. The protime is also within normal range which tells the physician that the extrinsic clotting mechanism involving factor VII is functioning properly. The APTT shows a defect in the intrinsic clotting mechanism. This points to a defect in factor VIII, IX, XI, or XII. Further testing is needed to tell which factor is abnormally low or missing in the blood.
Further comments: If the PT and APTT were both prolonged, an abnormality in the common pathway would be indicated. The common pathway involves factors I, II, V, and X.