Glutamine

This test measures the amount of glutamine in your blood, usually in plasma or serum. Glutamine is one of the most abundant amino acids in the body and serves as a building block for proteins. It is also a key fuel source for cells in the gut and immune system and helps carry nitrogen between tissues.

Glutamine levels are commonly checked as part of a quantitative amino acid profile when your clinician is evaluating metabolism, nutrition status, or suspected inborn errors of metabolism. Because glutamine is closely linked to how your body handles nitrogen and ammonia, it can provide clues about liver function and certain rare genetic conditions.

Abnormal glutamine levels can be a sign of how well your body is managing nitrogen and ammonia. High levels may occur when ammonia accumulates or when there are problems with the urea cycle, while low levels may reflect poor intake or absorption of protein, severe illness, or increased demand by tissues. Clinicians may order this test if you have symptoms such as unexplained vomiting, confusion, excessive sleepiness, breathing changes, or seizures, particularly in newborns and children, or if you have known liver disease.

The result can also help guide nutrition support. In people receiving tube feeding or intravenous nutrition, or those recovering from major surgery, burns, or infection, glutamine can shift as the body adapts to stress. Tracking it alongside other amino acids and ammonia helps your care team tailor treatment and monitor risk for complications.

Your result is interpreted using age-specific reference intervals and your clinical picture. A single value is less informative than the overall pattern of amino acids, ammonia levels, and your symptoms. If your result is higher than expected, your clinician may check ammonia, liver tests, and consider additional metabolic studies. If it is lower, they may review your diet, recent illnesses, and how your gut is functioning, and assess for increased needs during recovery from stress or injury.

Preparation and sample handling affect this test. Fasting or a light fast is often recommended, and the sample should be processed promptly, since glutamine can change if the blood sits before separation or is not kept cold. Do not start or stop supplements or medications without medical advice. Your provider will explain what the result means for you and whether more testing or nutrition changes are appropriate.