A female client with liver cirrhosis and chronic anemia is hospitalized for a deep venous thrombosis. The client is receiving a heparin infusion and suddenly develops epistaxis. Which laboratory value would indicate that the heparin infusion needs to be turned off?
a. Hematocrit of 30% (0.30)
b. Partial thromboplastin time of 10 seconds
c. Platelet count of 80,000/mm3 (80 x 10^9/L)
d. Prothrombin time of 11 seconds