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Test Code BARB Phenobarbital

Specimen and Container/Tube

Specimen Type: Serum

Preferred Specimen: Red Top

Other Acceptable specimens: Serum/Gold Top, Plasma/Li-Heparin Mint Top

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

  • Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent room temperature at 15-25oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.

Reference Values

Test

Age

Sex

Reference Range

Phenobarbital

All

All

15-40 μg/mL

Critical Values

Analyte

Unit

Low

High

Age

Phenobarbital

μg/mL

n/a

>60

All

CPT Codes

80184

LOINC Codes

3948-7

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

7 days

Refrigerated

7 days

Frozen

2 months

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Test Components

Phenobarbital
 

Clinical Indications

Used in the diagnosis and treatment of phenobarbital use or overdose and in monitoring levels of phenobarbital.

Methodology

Kinetic Interaction of Microparticles in solution (KIMS) (Roche Diagnostics)

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • Monitoring of the serum level of the drug is essential in order to achieve maximal seizure control while maintaining minimal blood levels to avoid negative side effects.
  • Variation in metabolism and absorption of the drug may cause levels to rise above 40 μg/mLor fall below 15 μg/mL.

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: 1 hour

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Synonyms/Keyword Search

PHNO2, PHENO, BARB, Phenobarb

Last Review Date

8/19/2024