Final answer:
The International Normalized Ratio (INR) is the blood test used to monitor a patient's response to Coumadin therapy and assist in dosage adjustments. It measures blood clotting time and reflects how well the anticoagulant is working, which is crucial for preventing thrombotic events while managing bleeding risks.
Step-by-step explanation:
The blood test performed to monitor a patient's response to Coumadin therapy and to aid in adjusting Coumadin dosage is the International Normalized Ratio (INR).
Coumadin, also known as warfarin, is an anticoagulant medication used to prevent harmful blood clots that might lead to a stroke or heart attack. The INR is a standardized number that's calculated based on the results of a prothrombin time (PT) test. This test measures how long it takes for blood to clot. The liver produces coagulation factors, and if the INR is increased, it indicates that the blood is taking longer than usual to clot, which could suggest that the patient is at reduced risk of forming blood clots, but also at potentially increased risk of bleeding. Adjusting the Coumadin dose can help control the balance between preventing clots and causing excessive bleeding.
The other options listed, such as C-reactive protein, Fasting blood glucose, and Hemoglobin A1c, monitor inflammation, blood sugar levels, and long-term control of diabetes, respectively, but are not used to adjust Coumadin dosage.