CPT Code


Specimen Type


Container Type

Green-Lithium Heparin


4 hours @ 2-4° C or 3 weeks @ -20° C

Handling Instructions

Completely fill tube with blood, place on ice, let it chill, centrifuge within 15 minutes (cold), separate plasma and submerge in ice until analysis; No ammonium heparin tubes.

Clinical Notes

Ammonia is a waste product formed primarily by bacteria in the intestines during the digestion of protein. If not processed and cleared from the body appropriately, excess ammonia can accumulate in the blood. This test measures the amount of ammonia in the blood. Ammonia is normally transported in the blood to the liver, where it is converted into two substances called urea and glutamine. The urea is then carried to the kidneys, where it is eliminated in the urine. If this “urea cycle” does not complete the breakdown of ammonia, ammonia builds up in the blood and can pass from the blood into the brain.