Plasma amino acids

Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand. In infants or young children, a sharp tool called a lancet may be used to puncture the skin. The blood collects in a small glass tube called a pipette, or onto a slide or test strip. A bandage is put over the spot…

The person having the test may be asked not to eat 3 or more hours before the test. Check with your child's health care provider for specific advice.

There might be slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn. The needle stick will probably cause an infant or child to cry.

This test is done to measure the level of amino acids in the blood. An increased level of a particular amino acid shows that there is a problem with the body's ability to break down (metabolize) that amino acid. The test may also be used to look for decreased levels of amino acids in the blood. Increased or decreased…

All measurements are in micromoles per liter (µmol/L). Normal values may vary between different laboratories. Talk to your health care provider about your specific test results. Alanine: Children: 200 to 450 Adults: 230 to 510 Alpha-aminoadipic acid: Children: not detected Adults: not detected Alpha-amino-N-butyric…

An increase in the total level of amino acids in the blood may be due to: Eclampsia Inborn error of metabolism Fructose intolerance Ketoacidosis (from diabetes) Kidney failure Reye syndrome Laboratory error A decrease in the total level of amino acids in the blood may be due to: Adrenal cortical hyperfunction Fever…

Screening infants for increased levels of amino acids can help detect problems with metabolism. Early treatment for these conditions may prevent complications in the future.

Dietzen DJ, Vieira Willrich MA. Amino acids, peptides, and proteins. In: Rifai N, Chiu RWK, Young I, Burnham C-A D, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 31. Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Defects in metabolism of amino…