Oxycodone (Free) Mass Concentration in Serum/Plasma

Why This Test Is Done

Your healthcare provider may order this test if you’re taking oxycodone (a pain reliever) and want to monitor how much of the drug is actually circulating in your blood in its active, free form. This can be important for managing pain, preventing overdose, or adjusting your dose if you experience side effects like drowsiness or respiratory issues.

What to Expect Before the Test

No special preparation is typically needed. You may have a small needle inserted into a vein (venipuncture) in your arm to draw blood. If you’re concerned about needles, let your healthcare provider know. You can eat and drink normally unless instructed otherwise.

What the Test Results Mean

Free oxycodone levels help determine whether your dose is therapeutic (effective for pain relief) or too high (potentially dangerous). Unlike total oxycodone, which includes both free and bound forms, free levels focus on the active portion that interacts with your body’s receptors.

Common Reasons for Monitoring

This test is often used in patients who are: - Taking high doses of oxycodone for chronic pain, - At risk for opioid-related side effects, - Undergoing treatment for opioid use disorder, - Or experiencing unexplained symptoms like confusion or slowed breathing.