Final Answer:
When a patient taking warfarin informs a phlebotomist, the phlebotomist should recognize that the International Normalized Ratio (INR) test results may be affected.
Step-by-step explanation:
Warfarin is an anticoagulant medication commonly prescribed to prevent blood clots. The INR test measures the blood's ability to clot and is crucial for monitoring patients on anticoagulants. Warfarin interferes with the clotting process, and monitoring the INR helps ensure that the medication is administered at appropriate levels to prevent both excessive bleeding and clot formation. If a patient is taking warfarin, the phlebotomist should be aware that the INR test results may be influenced by the medication, and this information is vital for the healthcare provider to make informed decisions about the patient's treatment plan.