Phenobarbitone

Alternative names, keywords

Phenobarbital

Samples required

● Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples.

20 days to steady state.

Test indications

Test information

For primidone (Mysoline) requests, phenobarbitone will be assayed as it is the major active metabolite.

Factors affecting test performance/ results

In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.

Results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.

Reference range

Therapeutic range 10 - 30 mg/L
_{Source: Roche Cobas^® Phenobarbitone kit insert 2024-02, V6.0}

Turnaround time

RSCH same day (if urgent, within 2hr), PRH 24h (4hr if urgent)

Enquiries

Biochemistry (Automation)