Prothrombin Time and Partial Thromboplastin Time (PT and PTT) LabCorp

This test includes both Partial Thromboblastin Time (PTT) and Prothrombin Time (PT). Below is a breakdown of each test:

Prothrombin Time (PT) - Used for the evaluation of the extrinsic coagulation system and aids in screening for congenital and acquired deficiencies of factors II, V, VII, X, and fibrinogen. This test is used clinically for the therapeutic monitoring of warfarin (Coumadin®) anticoagulant therapy. 

Partial Thromboplastin Time (PTT) - The activated Partial Thromboplastin Time (aPTT) is sensitive to deficiency or inhibition of factors in the intrinsic pathway. These include the contact factors; high molecular weight kininogen (HMWK), prekallikrein, and factor XII along with procoagulant factors XI, IX, and VIII. The aPTT is less sensitive to deficiencies of X, V, prothombin, and fibrinogen. Nonspecific, lupus-type anticoagulants can also extend the aPTT, but the more sensitive aPTT-LA test should be used to screen for this condition.