From Health Facts
Latest Edit: Hector 2014-03-24 (EDT)
|See Also||Lab Tests|
This test is used to assess the adequacy of the extrinsic system and common pathway in the clotting mechanism.
- The hemostatic and coagulation system consists of a homeostatic balance between factors encouraging the clotting and factors encouraging clot dissolution.
- The PT measures the clotting ability of factors I (fibrinogen), II (prothrombin), V, VII, and X, which are clotting factors in the extrinsic system and coagulation pathway
- When these clotting factors exist in deficient quantities, the PT is prolonged
- No fasting required.
- Factors which can cause increased levels
- Drugs: Allopurinol, aminosalicylic acid, barbiturates, beta-lactam antibiotics, chloral hydrate, cephalothins, chloramphenicol, chlorpromazine (Thorazine), cholestyramine, cimetidine, clofibrate, colestipol, ethyl alcohol, glucagon, heparin, methyldopa (Aldomet), neomycin, oral anticoagulants, propylthiourcil, quinidine, quinine, salicylates, and sulfonamides
- Factors which can cause decreased levels
- A diet high in fat or leafy vegetables
- Drugs: Anabolic steroids, barbiturates, chloral hydrate, digitalis, diphenhydramine (Benadryl). estrogens, griseofulvin, oral contraceptives, and vitamin K
High levels indicate:
- Liver disease
- Hereditary factor deficiency
- Vitamin K deficiency
- Bile duct obstruction
- Coumarin ingestion
- Disseminated intravascular coagulation (DIC)
- Bleeding time, Thrombin time, Partial thromboplastin time, Coagulating factor concentration
- Pagana Kathleen D, Pagana Timothy J (2006) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby.