Ammonia

Message

Must be collected at an Inova facility in a chilled specimen tube.

Centrifuge within 15 minutes and transport on wet ice.

Test Code

AMON

Alias/See Also

Epic: LAB47

NH3 (Ammonia), Plasma

CPT Codes
82140

Preferred Specimen

Specimen Type: Plasma
Collection Container: Green top (Lithium heparin)
Specimen Volume: 3 mL

Minimum Volume

0.20 mL

Instructions

Collection Instructions:

Completely fill the collection tube and thouroughly mix.
Immediately place on ice.
Deliver to the lab within 15 minutes.

Additional Information: Additionaly, plasma can be poured off and frozen and stored/transported.

Transport Container

Plastic vial

Specimen Stability

Room temperature: Unacceptable
Refrigerated: 2 hours
Frozen: 21 days

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

Unlabeled, mislabeled, wrong tube type, QNS, lipemic, hemolyzed.
Received room temperature
Received not on ice

Methodology

Glutamate Dehydrogenase.

Setup Schedule

Daily

Report Available

Same day

Limitations

Do not use hemolyzed or lipemic specimens.

Reference Range

18-72 μmol/L

Clinical Significance

Intestinal bacteria catabolyzes amino acid, generating NH3. Liver hepatocytes convert it into non-toxic urea. However, excess of ammonia can have a toxic effect on the central nervous system. Elevated ammonia levels may be seen with severe liver failure (Reye's syndrome), viral hepatitis, or cirrhosis. Elevated ammonia levels have also been reported with patients taking valproic acid.

Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031

Last Updated: March 3, 2023
Last Review: N. Wolford, March 3, 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.