Specimen:

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

2 mL whole blood in light green top tube or 2 microtubes for pediatric 
patients

Rejection Criteria:

Avoid hemolysis

Testing Schedule:

24 hrs/day, 7 days a week, including holidays.

Analytic Time:

2 hours (upon receipt in laboratory)

Reference Range:

1.5-2.9 mg/dl

Critical value: <1.0 mg/dl and >4.7 mg/dl

Test
Limitations:

Criterion: Recovery within plus or minus 10% of initial values

Plasma
Icterus: No significant interference up to an I index of 65 (conjugated 
bilirubin) and an I index of 37 (unconjugated bilirubin) corresponding 
to an approximate bilirubin concentration of 65 mg/dl (conjugated) and 
37 mg/dl (unconjugated).

Hemolysis interferes due to magnesium released from erythrocytes.

Lipemia (Intralipid): No significant interference up to an L index of 
400 (approximate triglycerides concentration: 800 mg/dl). There is poor 
correlation between turbidity and triglycerides concentration.

In-vitro tests were performed on 34 commonly used pharmaceuticals.

No interference with the assay was found.

Reference:
Glick MR, Ryder KW, Jackson SA. Graphical Comparisons of Interferences 
in Clinical Chemistry Instrumentation. Clin Chem 1986;32:470-474.

Methodology:

Colormetric endpoint

CPT Code:

83735

See Additional Information:
Chemistry Critical Lab Values