Prothrombin Time
Sample: Plasma (Citrate)
Schedule: Daily
Units: Seconds
Range: 11,5 - 13,5 (without anticoagulant treatment)
Remarks: See INR (International Normalized Ratio), which applies to the international normalized measurement of the Prothrombin Time, and is calculated as: INR = (Prothrombin time / Control time) ISI , where ISI = International Sensitivity Index and is given by the manufacturer of the reagents used in the test. The INR test is used to evaluate the extrinsic cascade system of coagulation as it is sensitive to decreased values of Factors II, V, VII or X. INR is widely use in monitoring the anticoagulant therapy of warfarin type or in evaluation of liver failure, hereditary coagulation disorders, Vitamin K deficiency, disseminated intravascular coagulation and homeostasis studies. INR is not sensitive to deficiencies either in the intrinsic system (Factors VIII, IX, XI and XII) or to platelets disorders.
