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Test Code PHNO Phenobarbital, Plasma or Serum

Additional Codes

LAB30

Methodology

Used for therapeutic drug monitoring.

Performing Laboratory

St. Mary's Regional Medical Center-Chemistry

 

CPT: 80184

Specimen Requirements

Submit only 1 of the following specimens:

 

Plasma

Container/Tube: Light green-top (lithium heparin) tube

Specimen: 1 mL of lithium heparin plasma

Transport Temperature: Ambient

Collection Instructions: Draw specimen just prior to administration of next dose for therapeutic response.

Note:

1. Indicate plasma.

2. Label specimen appropriately (plasma).

 

Serum

Container/Tube: Plain, red-top tube or serum gel tube

Specimen: 1 mL of serum

Transport Temperature: Ambient

Collection Instructions: Draw specimen just prior to administration of next dose for therapeutic response.

Note:

1. Indicate serum.
2. Label specimen appropriately (serum).

Reference Values

15-40 mcg/mL

Concentrations greater than 50 mcg/mL are often associated with toxic symptoms.

Note: Primidone and mephobarbital are metabolized to phenobarbital. Dosage adjustments are made after 2 weeks of therapy to achieve steady-state blood levels.

Day(s) Test Set Up

Monday through Sunday

Available STAT