Specimen

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

2 ml; light green top tube or one 0.4 ml microtubes.  (Sufficient for 
one or more anticonvulsant drugs).

Testing Schedule:

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

Analytic Time:

3 hours (upon receipt in laboratory)

Reference Range:

15-40 mcg/ml

Critical value: >60 mcg/ml

Test
Limitations:

Criterion: recovery plus or minus 1.2 ug/ml of initial value at 
concentrations less than 12 ug/ml or plus or minus 10% of initial value 
at concentrations greater than 12 ug/ml.

Icterus: No significant interference up to an I index of 60 
(approximate bilirubin concentration: 60 mg/dl).

Hemolysis: No significant interference up to an H index of 1000 
(approximate hemoglobin concentration: 1000 mg/dl).

Lipemia (Intralipid): No significant interference up to an L index of 
1000 (approximate triglyceride concentration: 2000 mg/dl). There is 
poor correlation between turbidity and triglycerides concentration.

Total Protein: No significant interference up to a concentration of
12.8 g/dl.

Rheumatoid factor: No significant interference up to a concentration of 
180 IU/ml.

Mephobarbital (greater than 100%) and amobarbital (greater than 20%) 
show significant cross-reactivity.

As with any assay employing mouse antibodies, the possibility exists 
for interference by human anti-mouse antibodies (HAMA) in the sample, 
which could cause falsely elevated results.

The incidence of patients with antibodies to E. coli beta 
-galactosidase is extremely low. However, some samples containing such 
antibodies can result in artificially high phenobarbital results that 
do not fit the clinical profile. If this occurs, contact Customer 
Technical Support.

Methodology:

EIA (Enzymatic ImmunoAssay)

CPT Code:

82205

See Additional Information:
Chemistry Critical Lab Values