Ammonia, Plasma CPT: 82140

Expected Turnaround Time

Within 1 day

Specimen Requirements


Plasma EDTA


1 mL

Minimum Volume

0.5 mL


Lavender top (EDTA)


1. Specimens should be put on ice immediately after collection.

2. Centrifuge at refrigerated temperature (4 degrees C).

3. Aliquot plasma into plastic screw-top tube. Keep on ice.

4. Freeze plasma within 2 hours of draw.

Storage Instructions

Maintain specimen at room temperature.

Stability Requirements

Temperature Period
Room TemperatureNot recommended
Refrigerated3 hours
Frozen24 hours
Freeze/thaw/ cycles stable x 3

Patient Information

To detect an elevated level of ammonia in the blood that may be caused by severe liver disease, kidney failure, or certain rare genetic disorders; to help investigate the cause of changes in behavior and consciousness; to help diagnose hepatic encephalopathy or Reye syndrome

When someone with or without liver disease or kidney failure experiences mental changes or lapses into a coma; when a newborn experiences frequent vomiting and increased lethargy or when a child has continuous vomiting and unusual sleepiness during recovery from a viral illness, such as the flu or chickenpox

A blood sample drawn from a vein.