Test Details
Methodology
Total: immunoassay; Free: ultrafiltrate assayed by immunoassay
Result Turnaround Time
2 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Evaluate toxicity; monitor therapeutic levels
Specimen Requirements
Specimen
Serum or plasma
Volume
3 mL
Minimum Volume
2.3 mL
Container
Red-top tube or green-top (heparin) tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.
Collection Instructions
Transfer separated serum or plasma to a plastic transport tube. Collect specimen just prior to next dose. Serum or plasma must be separated from cells within 45 minutes of collection. Send serum or plasma in a plastic transport tube.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Storage Instructions
Room temperature
Causes for Rejection
Gel-barrier tube; hemolysis; lipemia
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 070706 | Phenytoin,Free and Total,Serum | 34540-5 | 070778 | Phenytoin, Serum | ug/mL | 3968-5 |
| 070706 | Phenytoin,Free and Total,Serum | 34540-5 | 070763 | Phenytoin, Free, Serum | ug/mL | 3969-3 |
| Order Code | 070706 | |||||
| Order Code Name | Phenytoin,Free and Total,Serum | |||||
| Order Loinc | 34540-5 | |||||
| Result Code | 070778 | |||||
| Result Code Name | Phenytoin, Serum | |||||
| UofM | ug/mL | |||||
| Result LOINC | 3968-5 | |||||
| Order Code | 070706 | |||||
| Order Code Name | Phenytoin,Free and Total,Serum | |||||
| Order Loinc | 34540-5 | |||||
| Result Code | 070763 | |||||
| Result Code Name | Phenytoin, Free, Serum | |||||
| UofM | ug/mL | |||||
| Result LOINC | 3969-3 |