Prothrombin Complex Activity (Serum/Plasma) with INR Calculation

Why This Test Matters

Your body needs a balanced mix of clotting factors to stop bleeding when you cut or injure yourself. This test checks how effectively these factors work together to form a clot. An abnormal result may indicate conditions like vitamin K deficiency, liver disease, or blood clotting disorders.

How the Test Works

A small blood sample is taken and mixed with a special reagent. The time it takes for a clot to form is measured. The INR is then calculated by comparing your result to a standard value, accounting for differences in lab methods.

Common Conditions Monitored

This test is often used to monitor patients on blood thinners (like warfarin) to prevent excessive bleeding or clots. It’s also helpful in diagnosing or managing conditions like liver disease, bleeding disorders, or inherited clotting problems.

What to Expect Before the Test

No special preparation is needed, but inform your doctor if you’re taking blood thinners, have recent surgery, or have any bleeding disorders. Avoid aspirin or other NSAIDs for a few days before testing if advised by your provider.