Acetaminophen
Order Code: APAP
Order Form: Laboratory Requisition
Specimen:
Plasma
Collection Medium:
Plasma Separator Tube
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL; light green top tube or ONE microtainer.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
Acetaminophen concentrations greater than 150 mcg/mL at four hours after ingestion or greater than 40 mcg/mL at 12 hours after ingestion are often associated with toxicity. Critical value: >40 mcg/mL
Test Limitations:
Hemolysis: No significant interference up to an H index of 150 (approximate hemoglobin concentration: 150 mg/dL).

Lipemia: No significant interference up to an L index of 1600 (approximate triglycerides concentration: 3200 mg/dL). Note there is poor correlation between turbidity and triglyceride concentration.

Icterus: Icterus can cause positive interference with the acetaminophen assay. Specimens with an icteric index of 20 or greater (approximate total bilirubin concentration of 20 mg/dL) can cause acetaminophen results exceeding 5 mcg/dL in acetaminophen-free samples. Testing is cancelled with an icteric index of 30 or greater. At an icteric index of 30 or above, interferences exceeding 20 mcg/dL acetaminophen may be seen.
Methodology:
Colorimetric
Sample Processing:
Centrifuge at 3000 RPM for 10 minutes.
Aliquot plasma into labeled container and cap.
Sample Storage:
Refrigerate.
Transport Instructions:
Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.
CPT Code:
82003
 
See Additional Information:
Chemistry Critical Lab Values