Test Directory

Test Code
DILN
Test Name
Phenytoin, Total
CPT Codes
80185
Expected Turnaround Time
1 day
Clinical Utility
Used to measure the amount of phenytoin in the blood and to determine if the drug concentration is within the therapeutic range.
Specimen and Container Info

Specimen Types: Serum or Plasma

Collection Containers:

  • Gold Top, Serum Separator
  • Light Green Top, Plasma Separator
  • Red Top, Separator

Minimum Acceptable Volume: 0.4 mL

Processing and Submission Instructions

Separator tubes: Contains clot activator and gel for separating serum from cells, but not anticoagulant. Separate serum from cells as soon as the clot has formed (30 minutes). If specimen is centrifuged before clotting is complete, a fibrin clot will form on top of the cell. This may cause the gel barrier to not be intact and could cause improper separation of serum and cells, possibly affecting test results.

Tubes with anticoagulant: To ensure accurate test results, all tubes containing an anticoagulant or preservative must be allowed to fill completely. Attempts to force more blood into the tube by exerting pressure, as in collection with a syringe, will result in damage to the red cells (hemolysis).

Transport Instructions

Transport to the laboratory refrigerated.

Stability Requirements

Refrigerated

5 days
Methodology
Enzyme Immunoassay
Reference Intervals
Critical Values
Performing Location
Cedar Crest Hospital, Dickson City Hospital, Hazleton Hospital, Hecktown Oaks Hospital, Muhlenberg Hospital, Pocono Hospital, Redeemer Health, Roble Road Core Laboratory, Schuylkill Hospital
Testing Schedule
Routine daily, STAT testing available