Final answer:
When a patient taking warfarin undergoes blood collection, coagulation tests may be affected. The INR, which measures the speed of a specific pathway of coagulation, will be increased in patients on warfarin.
Step-by-step explanation:
Medicine
When a patient taking the anticoagulant medication warfarin undergoes blood collection, it can affect coagulation tests. Warfarin inhibits the production of vitamin K-dependent clotting factors in the liver, leading to prolonged clotting times. Therefore, tests such as the prothrombin time (PT) and international normalized ratio (INR) may be affected by this medication.
For example, the INR measures the speed of a specific pathway of coagulation and compares it to normal. A higher INR indicates that clotting takes longer than usual. Since warfarin affects clotting, the INR will be increased in patients taking this medication.