Phenobarbital

Casandra

Casandra Test Code AR61885Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 0090230CPT Code 80184

Also known as: PHNO

Clinical Use

Order Test

Use

Phenobarbital testing is used to optimize drug therapy and monitor patient adherence. Therapeutic drug monitoring helps ensure effective treatment outcomes and minimizes toxicity. Phenobarbital is commonly used as an anticonvulsant to treat seizure disorders and manage status epilepticus. Monitoring its levels is crucial for determining the correct dosage for individual patients.

Special Instructions

The specimen should be collected in a plain red top tube or a green (sodium heparin) tube. It is important to separate serum or plasma from cells as soon as possible or within 2 hours of collection to prevent any alterations in the specimen that might affect test results. The specimen should then be transferred to an ARUP standard transport tube for shipping. As per New York state regulations, this test is approved for use.

Limitations

This test is limited by the specimen conditions at the time of collection and processing. Separator tubes, gels, lavender (EDTA), and gray (sodium fluoride/potassium oxalate) tubes, as well as hemolyzed specimens, are unacceptable and may result in rejection of the specimen. The stability of the specimen can also affect results; therefore, following proper storage and handling is essential. After separation from cells, the serum is stable for 2 days at ambient temperature, and up to 6 months if refrigerated or frozen.

Test Details

New York Approved

Methodology

Immunoassay (Other)

Biomarkers

Phenobarbital

Analyte

Concentration • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Result Codes

3948-7

Result Turnaround Time

1 day

Specimen

Serum

Volume

1 mL

Minimum Volume

0.5 mL

Container

ARUP standard transport tube

Collection Instructions

Allow specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP standard transport tube. (Min: 0.5 mL)