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Test Code Pheny Grp Phenytoin, Free And Total

Important Note

This test includes a free and total Dilantin level. A total Dilantin will not be run at CHRMC unless specifically requested.

Clinical System Name

Phenytoin, Free And Total


Dilantin, Free And Total

Sample Requirements

Specimen: Whole Blood

Container(s): Red or Gold SST or Dark Green/Sodium Heparin

Preferred Vol: 2 mL

Minimum Vol:


Note:  Draw just prior to next dose. Avoid hemolysis.


Indicate on requisition that total is to be done at CHRMC Lab if result of Total Phenytoin is needed stat.

Processing Instructions

Reject due to:

Spin: Y

Aliquot: Y

Temp: -20 C

Storage location: CPA freezer.

Order a PHENYTOIN and a PHENY GRP if requisition indicates total is to be run at CHRMC Lab stat.



Off-site collection:


Specimen Type Temperature Time
Serum or plasma Room temp  N
  Refrigerated  24 h
  Frozen  Y



STAT Performed TAT
N Daily 1 - 3 d


Performing Laboratory

Harborview Medical Center



Harborview Medical Center

Room GWH47; 325 9th Ave
Seattle, WA 98104

Phone Number: (206) 744-3451


Reference Range


  Free Phenytoin Total Phenytoin
Therapuetic 1.00 - 2.00 uG/mL 10 - 20 uG/mL
Toxic   >25 uG/mL

Free/Total ratio: 8 - 14%




Method: EMIT

Analytical Volume: 0.5 mL serum or plasma


CPT Codes



Send Out Instructions


Reference Test Name: Phenytoin - Free and Total
Reference Test Number: FTDIL
Instructions: Send out Monday thru Friday with the UW/HMC courier. Keep a copy of the Batch Sheet for our records.