What laboratory finding would likely indicate a deficiency in factor V?

A deficiency in factor V typically leads to a prolongation of the prothrombin time (PT). Factor V is essential for the coagulation cascade, specifically acting as a co-factor for prothrombin (factor II) to convert into thrombin. Proper functioning of the extrinsic pathway, which is assessed by the PT, depends significantly on factor V. When factor V is deficient or absent, the activation of the extrinsic pathway is impaired, resulting in an increased PT.

In contrast, the normal prothrombin time would suggest that factor V is functioning adequately, thus eliminating that option. Increased bleeding time is more indicative of platelet function issues rather than a deficiency in coagulation factors such as factor V. Finally, a normal partial thromboplastin time indicates that the intrinsic and common pathways of coagulation are intact, which does not align with the consequences of a factor V deficiency.

In summary, a prolonged prothrombin time reflects the disruption in the coagulation cascade due to factor V deficiency, making it the correct indication in this context.