| Ordering Code | 441 |
|---|---|
| Test Name | Phenobarbital |
| Alias | Luminal Barbita Solfoton PBARB |
| Preferred Specimen | Plasma |
| Preferred Container | Lithium Heparin PST (Green) |
| Other Specimen/Container | Plasma in EDTA, K2 (Lavender), Serum in SST (Gold), Serum in Plain (Red) |
| Optimum Volume | 1 mL |
| Collection Instructions | It is recommended to measure the steady-state concentration representing the trough level just before the next scheduled dose. |
| Handling Instructions | All specimen types must be centrifuged within 2 hours of collection. If no gel separation present in tube and testing is delayed, plasma/serum is aliquoted from cells within 2 hours of collection Send aliquot if transport time >24 hours. |
| Transport Requirements | Oahu: Refrigerated Airline: Refrigerated (Aliquot) |
| Specimen Stability | Refrigerated: 24 Hours (Centrifuged, unaliquoted gel separator tubes), 1 Month (Aliquot) Frozen: 3 Months (Aliquot) Frozen samples should be thawed only once Test cannot be added to >24 hours unaliquoted specimens collected in a gel separator tube. |
| Rejection Criteria | Grossly hemolyzed, Insufficient quantity, Specimen older than stability limits, Uncentrifuged gel separator tube specimens >2 hours old, Unaliquoted gel separator tube specimens >24 hours old |
| Avail. Stat | YES |
| Analytic Time | 1 Day |
| Methodology | Homogenous Enzyme Immunoassay (EMIT) |
Reference range(s)
The reference ranges listed below are valid on this date of March 12, 2026.
| Component | Age | Male Norm | Male Critical Low | Male Critical High | Female Norm | Female Critical High | Female Critical Low | Units | Add'l info |
|---|---|---|---|---|---|---|---|---|---|
| Phenobarbital | ALL | 10.0-40.0 | >= 50.0 | 10.0-40.0 | >= 50.0 | ug/mL |