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Test Code MISCLM Phenytoin, Free, Serum

Additional Codes

 

MAYO Test ID

PNYF

EPIC Test ID

2608

 

Useful For

Monitoring for appropriate therapeutic concentration of free phenytoin: free phenytoin level is the best indicator of adequate therapy in renal failure

 

Assessing compliance and toxicity

Method Name

Membrane Separation/Kinetic Interaction Microparticles in Solution (KIMS)

Reporting Name

Phenytoin, Free, S

Specimen Type

Serum Red


Specimen Required


Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 2 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial within 2 hours of collection.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 7 days
  Frozen  14 days
  Ambient  7 days

Reject Due To

Gross hemolysis Reject

Reference Values

Therapeutic: 1.0-2.0 mcg/mL Critical value: ≥2.5 mcg/mL

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PNYF Phenytoin, Free, S 3969-3

 

Result ID Test Result Name Result LOINC Value
PNYF Phenytoin, Free, S 3969-3

CPT Code Information

80186 

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.