The nurse is caring for a client admitted with bleeding tendencies. The physician suspects hemophilia. Which laboratory value supports the diagnosis? A. Prolonged aPTT B. Increased protime C. Abnormal fibrinogen level D. Increased platelet count

Hemophilia is a rare genetic bleeding disorder that affects the blood's ability to clot, causing excessive bleeding even from minor injuries. The two main types of hemophilia are hemophilia A and hemophilia B, both resulting from deficiencies in clotting factors VIII and IX, respectively.

Now, let's analyze the different lab values given in the options: A. Prolonged aPTT (activated partial thromboplastin time): aPTT is a test that measures the time it takes for blood to clot in a sample. A prolonged aPTT indicates a deficiency or dysfunction in the intrinsic and common clotting pathways, including factors VIII and IX. B. Increased protime (prothrombin time): Prothrombin time measures the clotting ability of the extrinsic and common pathways. An increase in protime suggests issues with clotting factors involved in these pathways (factors II, V, VII, and X). C. Abnormal fibrinogen level: Fibrinogen is a protein involved in the final stages of the clotting process, and an abnormal fibrinogen level suggests an issue with the production or function of fibrinogen itself. D. Increased platelet count: Platelets are small cells in the blood that help form clots to stop bleeding. An increased platelet count suggests that the number of platelets is not the cause of a bleeding disorder.

Based on our analysis of the given options, the laboratory value that best supports the diagnosis of hemophilia is prolonged aPTT (Option A). This is because a prolonged aPTT signals issues with the intrinsic and common clotting pathways that involve clotting factors VIII and IX, which are precisely deficient in hemophilia A and hemophilia B.