CPT/HCPCS
82140
Order Code
CH107
Turnaround Time
24-48 hours
Test Includes
Ammonia
Specimen Requirements
Specimen Source
Plasma
Transport Container
(Specimen Container)
(Specimen Container)
Lavender-top (EDTA) tube
Preferred Specimens
Plasma
Minimum Volume (uL)
.5 mL
Collection Instructions
(Transport Temperature)
(Transport Temperature)
Tube must be filled completely and kept tightly stoppered at all times. Mix well. Specimen must be placed on ice immediately. After collection, immediately centrifuge the lavender-top tube at room temperature, transfer plasma to a transport tube, and freeze. Label this tube ""Frozen Plasma"". Freeze. Ammonia is stable for several days at -20°C. Caution: Blood ammonia increases rapidly at room temperature. Transport Frozen.
Specimen Stability
| Temperature | Period |
|---|---|
| Room temperature | Unstable |
| Refrigerated | Unstable |
| Frozen | 21 days |
Reject Criteria
Received unfrozen:
Hemolysis
Lipemia
Whole blood
Received thawed
PPT Potassium EDTA (white-top) tube
Test Details
Methodology
Spectrophotometry
Clinical Significance
Ammonia is a waste product of protein catabolism; it is potentially toxic to the central nervous system. Increased plasma ammonia may be indicative of hepatic encephalopathy, hepatic coma in terminal stages of liver cirrhosis, hepatic failure, acute and subacute liver necrosis, and Reye’s syndrome. Hyperammonemia may also be found with increasing dietary protein intake.
The major cause of hyperammonemia in infants includes inherited deficiencies of urea cycle enzymes, inherited metabolic disorders of organic acids and the dibasic amino acids lysine and ornithine, and severe liver disease.
Reference Ranges
M:16-60 umol/L
F:11-5
