Phenytoin (Dilantin®), Free and Total, Serum
| Phenytoin (Dilantin®), Free and Total, Serum | | | |
| Number | | 070706 |
| CPT | | 80185; 80186 |
Synonyms | | Dilantin®, Free and Total |
| Specimen | | Serum or plasma |
| Volume | | 3 mL |
| Minimum Volume | | 1.3 mL |
| Container | | Red-top tube or green-top (heparin) tube |
| Collection | | Collect specimen just prior to next dose. Serum/plasma must be separated from cells within 45 minutes of collection. Transfer separated serum or plasma to a plastic transport 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. |
| Storage Instructions | | Refrigerate |
| Causes for Rejection | | Gel-barrier tube; hemolysis; lipemia |
| Use | | Evaluate toxicity; monitor therapeutic levels |
| Methodology | | Total: immunoassay; Free: ultrafiltrate assayed by immunoassay |
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