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Test Code PHENO Phenobarbital Level, LAB30

Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements

Container/Tube:

Preferred: Green-top (lithium heparin) tube

Acceptable: Gold-top serum gel tube, plain red-top tube, EDTA plasma, and Na-Heparin

Specimen Volume: A minimum volume of 1.2 µL plus a dead volume is required for testing.

Stability: Specimens are stable for 7 days at 25 ⁰C and 2-8 ⁰C or 1 year at -15 to -25 ⁰C.

Collection Instructions: Peak level should be drawn 1 to 3 hours post dose.

                                         Trough level should be drawn immediately prior to next dose.

Note: 1. Phenobarbital time to steady state is after 10 to 25 days of chronic oral dosing for adults                      and after 8 to 20 days of chronic oral dosing for children.

           2. Levels may be ordered at any time toxicity is suspected.

           3. Label specimen appropriately (plasma).

 

 

Reference Values

Therapeutic range: 10.0-30.0 mcg/mL

Critical value: >40.0 mcg/mL

Day(s) Test Set Up

Monday through Sunday

Useful For

Phenobarbital is an anticonvulsant and sedative-hypnotic drug used in the treatment of epilepsy, in particular for controlling focal motor or sensory seizures and grand mal seizures. Because of considerable inter-individual variation and the limited capacity for the liver to metabolize phenobarbital, blood concentrations should be monitored to obtain maximal anti-seizure effect.

Methodology

KIMS

Test Classification and CPT Coding

80184

Report Available

STAT within 1 hour upon receipt

Routine within 2 hours upon receipt