Ammonia

Test Code

AMON

CPT Codes
82140

Preferred Specimen

Lithium Heparin plasma (green top tube), placed on ice immediately after collection and transported immediately to lab.

Minimum Volume

0.5 mL

Other Acceptable Specimens

Lithium Heparin plasma (green top tube), centrifuged and plasma placed in plastic pourover container in freezer if transport to lab exceeds 20 minutes.

Instructions

After collection, place specimen on ice and transport immediately to lab. If transport time to lab will exceed 20 minutes, centrifuge specimen and transfer plasma to plastic pourover tube and place in freezer until courrier arrives.

Transport Container

Lithium Heparin plasma (green top) tube or, if freezing is required, centrifuged plasma in a plastic pourover tube.

Transport Temperature

Specimen should be on ice if transported to Medical Center Laboratory within 20 minutes of collection; Freeze plasma for courier transport to Medical Center Laboratory.

Specimen Stability

On ice - 20 minutes; Frozen - 24 hours

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

Hemolysis, Quantity not Sufficient, EDTA (purple top tube) contamination, IV contamination

Methodology
Colorimetric

Setup Schedule

Daily upon receipt

Report Available

Upon completion of analysis

Limitations

Glucose at 600 mg/dL (33.3 mmol/L) can cause a decrease of 8 to 40 Î¼mol/L in ammonia concentration.

Reference Range

9 - 30 umol/L

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 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.