Home
HelpTest Code PHNT Phenytoin
Additional Codes
| Epic Ordering Code | LAB31 |
| NBS code | LBC00780 |
| Service code | 31822 |
Specimen Requirements
Submit only one of the following:
| Preferred: | Acceptable: |
| Yellow Top | Light Green Top |
Processing Requirements
Allow specimen to clot for 30 mins (Yellow Top) and centrifuge within 2 hours
Specimen type: Serum
Volume: 0.5mL
Specimen Stability
| Specimen Type | Serum/Plasma |
|---|---|
| Ambient | 2 days |
| Refrigerate | 1 month |
| Frozen | 5 months |
Specimen Condition
| Haemolysis | OK |
|---|---|
| Icterus | OK |
| Lipaemia | OK |
| Others | Not applicable |
Methodology
Enzyme Immunoassay
Days and Times Performed
24 hrs, TAT 1 day
Reference Interval
| Therapeutic range | 10 – 20 mg/L |
|---|---|
| Critical value | > 20 mg/L |
Testing Laboratory
National University Hospital
Clinical Chemistry, 67724346
Useful For
Therapeutic drug monitoring.
Update
Last updated 26/07/2026
LOINC Code Information
3968-5
Alias
Dilantin