A child with prolonged aPTT underwent laparotomy and still did not develop any bleeding complications. Which of the following clotting factors is most likely to be deficient?

Ref: Nelson Textbook of Pediatrics, 18th editionExplanation:The dual mechanisms of activating clotting areA. Intrinsic - Surface activation -Measured by aPTTB. Extrinsic - Tissue factor mediated - Measured by PT* Deficiency of contact factors like Factor XII. prekallikrein & HMW Kininogen causes prolonged aPTT but no bleeding symptoms. (See the following table) Coagulation profile in common hematological conditionsDiseaseProthrombintime(PT)Partialthromboplastin lime (aPTT)BleedingtimePlateletcountBernard-Soulier syndromeUraffectedUnaffectedProlongedDecreased or unaffectedDisseminated intravascular coagulationProlongedProlongedProlongedDecreasedFactor XII deficiencyUnaffectedProlongedUnaffectedUnaffectedFactor V deficiencyProlongedProlongedUnaffectedUnaffectedFactor X deficiencyProlongedProlongedUnaffectedUnaffectedGlanzmann'sthrombastheniaUnaffectedUnaffectedProlongedUnaffectedHemophiliaUnaffectedProlongedUnaffectedUnaffectedLiver failure, earlyProlongedUnaffectedUnaffectedUnaffectedLiver failure end-stageProlongedProlongedProlongedDecreasedThrombocytopeniaUnaffectedUnaffectedProlongedDecreasedUremiaUnaffectedUnaffectedProlongedUnaffectedVitamin K deficiency or warfarin TherapyProlongedNormal or mildly prolongedUnaffectedUnaffectedVon Willebrand diseaseUnaffectedProlongedProlongedDecreased