If a partial thrombin time is high will the prothrombin also be high?

Not always: U mean: PTT vs. Pt? The partial thromboplastin time (PTT) measures the intrinsic pathway of the coagulation cascade; the protime (pt), the extrinsic. The pt is commonly affected by vitamin k antagonists (think: coumadin); the ptt, by heparin. Clotting factor deficiencies may also prolong both pt and ptt, but formal hematologist testing is required.

Not necessarily: Although these assays are quite similar, they are designed to test different components of the clotting cascade. The pt is used to monitor Coumadin (warfarin) and the PTT is typically used to monitor heparin.