Serum or plasma ornithine concentration (mass concentration)

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like fatigue, confusion, or unusual smells in your breath, which can indicate liver problems or metabolic disorders. It may also be part of routine testing for certain genetic conditions or after exposure to toxins that affect amino acid metabolism.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw. Avoid eating or drinking anything except water for that time. If you’re taking medications, let your provider know as they may affect results.

How the Test Works

A small sample of blood is taken from a vein in your arm. The sample is then sent to a lab where it is analyzed to measure ornithine levels using a specialized technique, often high-performance liquid chromatography (HPLC).

What the Results Mean

Results are compared to a general reference range, but exact values can vary by lab. Low levels may suggest liver disease, urea cycle disorders, or other metabolic issues, while very high levels could indicate certain genetic disorders or kidney problems. Your provider will interpret results in the context of your overall health.