Ammonia

Message

Place immediately on ice and centrifuge, preferably at 4^oC

Test Code

AMMON

Alias/See Also

AMON, NH3

CPT Codes
82140

Preferred Specimen

1.0 mL plasma collected in a Lavender (EDTA). Place immediately on ice. See special instructions in message field.

Patient Preparation
Patient should be fasting.
Smoking should be avoided prior to sampling.
Avoid contamination of samples by ammonia from smoking or traffic in laboratory or patient's room, glassware, or water.
Collect sample from stasis-free vein of patient (e.g., no tourniquet).

Minimum Volume

0.5 mL

Instructions

Place immediately on ice and centrifuge, preferably at 2-8 C.
Perform analysis 30 minutes of venipuncture or freeze seperated plasma into separate tube immediately.

Specimen Stability

Room Temperature: 15-25°C    30minutes after phlebotomy
Refrigerated: 2-8°C    30 min
Frozen: -38°C   3 weeks

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Grossly Hemolyzed, Lipemic, and Icteric are unacceptable

Methodology
Enzymatic

Setup Schedule

Mon-Sun

Report Available

In patient testing only - Same day
For outpatient testing see test code NH3REF

Reference Range

16-53 µmol/L

Clinical Significance

Ammonia is generated primarily in the gastrointestinal tract by metabolism of nitrogenous compounds. An excess of ammonia can be toxic to the central nervous system. The Krebs-Henseleit urea cycle provides a means of disposal of ammonia by metabolizing ammonia to urea in the liver.

Hyperammonemia in infants can be caused by inherited deficiencies of the urea cycle enzymes or acquired through acute (as in Reye’s syndrome) or chronic (as in cirrhosis) liver disease. In adults, elevated ammonia levels can aid in diagnosis of liver failure or hepatic encephalopathy from advanced liver diseases such as viral hepatitis or cirrhosis.

Performing Laboratory
Frederick Health Laboratory
400 W 7th Street
Frederick, MD 21701

Last Updated: July 11, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.