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Ammonia
MessageFor Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.
Test Code
NH3
Alias/See Also
70283;
NH3;
NH4;
NH4+;
Plasma Ammonia;
Ammonia Level
NH3;
NH4;
NH4+;
Plasma Ammonia;
Ammonia Level
CPT Codes
82140
Preferred Specimen
Frozen plasma collected in a K2EDTA Lavender Tube
Patient Preparation
• Do not utilize a tourniquet on patient if possible.
• Patient should not clench fist during collection as muscular exertion can increase 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.
• See chart below for specimen stability"
Minimum Volume
1 mL
Instructions
1. Collect sample in a K2EDTA Lavender tube ensuring tube is filled completely.
2. Invert tube gently 3-5 times.
3. Place specimen immediately on ice while awaiting centrifugation.
4. Centrifuge tube immediately after collection.
5. Transfer plasma to a labeled plastic transport tube within 20 minutes of collection.
6. Place transport tube in freezer or on dry ice within 30 minutes of collection.
If Unable to centrifuge and separate, patient must be referred to a CompuNet PSC for collection.
2. Invert tube gently 3-5 times.
3. Place specimen immediately on ice while awaiting centrifugation.
4. Centrifuge tube immediately after collection.
5. Transfer plasma to a labeled plastic transport tube within 20 minutes of collection.
6. Place transport tube in freezer or on dry ice within 30 minutes of collection.
If Unable to centrifuge and separate, patient must be referred to a CompuNet PSC for collection.
Transport Container
Plastic transport tube
Transport Temperature
Frozen K3EDTA Plasma
Specimen Stability
Plasma separated from cells
Room Temperature = 30 minutes
Refrigerated = 2 hour
Frozen = 72 hours
Room Temperature = 30 minutes
Refrigerated = 2 hour
Frozen = 72 hours
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis, Lipemia, incorrect specimen type, insufficient sample volume, improper storage conditions, exceeds specimen stability guidelines, contaminated sample.
Methodology
Spectrophotometric
Setup Schedule
24/7
AU
AU
Report Available
daily
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.
Performing Laboratory
CompuNet Clinical Laboratories, LLC
2308 Sandridge Drive
Moraine, OH 45439
Last Updated: May 13, 2025
