Test Code PTN Phenytoin (Dilantin) LAB31
Test Method
Turbidimetric Inhibition Immunoassay; Beckman DXC600
Specimen Requirement
0.5 mL serum or plasma is required.
Additional Specimen Collection Information
Collect blood in a lithium heparin, green-top or
red-top tube. Serum and plasma gel tubes are not
acceptable. Peak
specimens should be collected at least 6 hours after
last
dose. Trough level is collected just prior to next dose. Serum
or
plasma should be separated from contact with the cells within 2
hours of collection. Specimens not centrifuged within 4 hours
of
collection may be rejected. Refrigerate the specimen if
unable
to assay within 8 hours of collection. Samples with >4+
lipemia
must be cleared prior to analysis.
Reference Values
10.0-20.0 mcg/mL
-
Toxic Level: > 25 mcg/mL
Performance
Testing is performed Monday through Sunday.
Routine: Typically completed within 4 hours after the
specimen arrives at the testing site.
Expedite: Typically completed within 1 hour after the
specimen arrives at the testing site.
STAT: Typically completed within 30 minutes after the
specimen
arrives at the testing site.
Useful For
Monitoring for appropriate therapeutic concentration
Assessing compliance or toxicity
LOINC Code Information
3968-5 Phenytoin [Mass/Volume] In Serum Or Plasma
CPT Code Information
80185 Therapeutic Drug Levels: Phenytoin