Tail bleeding time and blood loss in platelet-specific PDI–deficient mice. Tails of WT (circle) and PDI CKO (triangle) mice were amputated, and bleeding time (A) was monitored as described in “Materials and methods.” (B) Blood loss during the bleeding time assay was determined by measuring the absorbance at 575 nm of hemoglobin (Hb). Horizontal bars represent the median of bleeding times and Hb content for each group of animals (n = 6).