Test Code: 5509
CPT Code: 82140
Alternative Name(s): Not applicable
Methodology: Enzymatic
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.
Supply: T59 - Lavender 4mL Blood Tube
Preferred Specimen: Plasma collected in a EDTA (lavender) tube
Preferred Volume: 2mL
Collection Instructions: Collect blood from stasis-free vein of patient (e.g., no tourniquet). Patient should not clench fist during collection, as muscular exertion often increases venous ammonia levels. Patient should avoid smoking prior to phlebotomy since smoking increases plasma ammonia levels. 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: Transport tube
Transport Temperature: Frozen
Specimen Stability: Frozen at -20C: 24 hours
Reject Criteria: Hemolysis
- What are hemolyzed specimens?
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Hemolysis occurs when the red cells are damaged during sample collection causing them to rupture. Hemolyzed serum or plasma is pale pink to red rather than the normal clear straw or pale-yellow color.
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- What causes a specimen to be hemolyzed?
- Mixing tubes too vigorously
- Placing tubes in the refrigerator without allowing 30 minutes at room temperature for complete clotting
- Exposure to heat or in a refrigerator that is too cold
- Using a needle with too small of a bore necessary for the venipuncture
- Using too large a tube when using a butterfly needle
- Not allowing sufficient time for alcohol to dry on puncture site
- Leaving the tourniquet on for longer than one minute
- How can hemolyzed specimens be prevented?
- For routine collections, use a 20–22-gauge needle
- Do not remove the needle from the vein with the vacuum tube engaged
- Do not collect a specimen in a hematoma
- Do not centrifuge the specimen for a prolonged period of time
- Draw the sample gently and evenly
- Received thawed
- PPT potassium EDTA (white-top) tube
For additional test, supply, or collection device information, please contact DLO's Customer Service at (800) 891-2917, option 2.
The CPT codes provided 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.