Ammonia, Plasma [5509X]

Test Code

55098

CPT Codes
82140

Preferred Specimen

2 mL frozen plasma collected in an EDTA (lavender-top) tube

Patient Preparation
Patient should avoid smoking before phlebotomy, since smoking increases plasma ammonia levels.

Minimum Volume

0.5 mL

Instructions

Collect blood from stasis-free vein of patient (e.g., no tourniquet).

Tubes should be filled completely and kept tightly stoppered at all times. Place immediately on ice. Separate plasma from cells within 15 minutes and freeze plasma immediately.

Transport Container

Plastic screw-cap vial

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 24 hours

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

Hemolysis • Received thawed • PPT potassium EDTA (white-top) tube

Methodology
Enzymatic

Setup Schedule

Set up: Daily; Report available: Next day

Reference Range

≤72 umol/L

Clinical Significance

Ammonia is one of the by-products of protein metabolism. Elevated blood ammonia levels have been associated with severe liver dysfunction such as hepatic encephalopathy, coma resulting from cirrhosis, severe hepatitis, Reye's syndrome and drug hepatotoxicity. Also, elevated blood ammonia has been reported in cardiac failure, azotemia, and pulmonary emphysema. Correlation between plasma ammonia and the degree of encephalopathy can be erratic.

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.