<prompt> In hemophilia, which of the following is raised: September 2007BTCTPTaPTT  <response>: Ans. D: aPTT Hemophilia A is a recessive X-linked genetic disorder involving a lack of functional clotting Factor VIII and represents 80 of haemophilia cases. Hemophilia B is a recessive X-linked genetic disorder involving a lack of functional clotting Factor IX. It comprises approximately 20 of haemophilia cases. Haemophilia C is an autosomal genetic disorder i.e. not X-linked involving a lack of functional clotting Factor XI. Haemophilia C is not completely recessive: heterozygous individuals also show increased bleeding Prolonged APTT may indicate: Use of heparin or contamination of the sample Antiphospholipid antibody especially lupus anticoagulant, which paradoxically increases propensity to thrombosis Coagulation factor deficiency e.g. hemophilia Shoening of the PTT has little clinical relevance. Normal PTT times require the presence of the following coagulation factors: I, II, III, IV, V, VI, VIII, IX, X, XI, and XII. Notably, deficiencies in factors VII or XIII will not be detected with the PTT test. 