Ammonia

Test Code

LAB47

Alias/See Also

NH3

CPT Codes
82140

Instructions

All outpatient ammonia draws should be performed at CHOMP Main Laboratory. No satellite or office draws will be accepted. Routine venipuncture. Light Green top (heparin) tube. Tubes should be filled completely, mixed by gentle inversion, placed on ice, and analyzed within 30 minutes.

Specimen Stability

Store on ice, stable 30 minutes.

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

Improper specimen handling (not chilled upon collection); hemolysis; not available to be analyzed within 30 minutes

Methodology
Colorimetric

Setup Schedule

Daily

Report Available

Within 1 hour

Reference Range

9.0-30.0 µmol/L

Clinical Significance

Circulatory ammonia level in normal individuals is relatively low despite the fact that ammonia is continuously produced from dietary and amino acid metabolism. Monitoring blood ammonia levels can be useful in the diagnosis of hepatic encephalopathy and hepatic coma in the terminal stages of liver cirrhosis, hepatic failure, acute and subacute necrosis, and Reye syndrome. Hyperammonemia in infants may be an indicator of inherited deficiencies of the urea cycle metabolic pathway.

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.