Sign in →

Epic Code LAB176 Phenytoin, Free and Total, Blood Level

Test Name Alias

Phenytoin Free and Total Blood Level | Dilantin | Diphenylhydantoin | 8327

Interface Order Alias

10219

Collection Instructions

Specimen Collection: Blood

 

Container(s): 4.5 mL Mint Green Top (Lithium Heparin Gel) or 5.0 mL Gold Top (Serum Separator-SST Gel)*

Preferred Volume to Collect: 4.5 mL

Minimum Volume to Collect: 2.0 mL

Neonate Volume to Collect: 1.0 mL

Capillary collect ok? Yes

Microtainer acceptable: Yes

 

Collection Instructions:

  • Inpatients: Please contact your local inpatient pharmacy for information regarding appropriate timing for blood drug level orders, if needed.
  • Indicated date and time of last dose.
  • Specimen usually collected as trough level.

  • Avoid gross hemolysis

  • After collection, gently invert tube 8-10 times.
  • Specimen should be processed within 2 hours – See Processing Instructions.

*Red top (plain) or Green top (Lithium Heparin, Non-Gel) are also acceptable specimen containers.

 

Processing Instructions (Laboratory, Outpatient or Off-site collection)

Processed Specimen: Plasma or Serum

Centrifuge/Spin: Yes

Aliquot: Yes

 

Processing Instructions:

  • Plasma is preferred specimen type
  • Green Tube/Plasma: Centrifuge after collection.
  • Gold Tube/Serum: Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours.

Transport Temperature: Refrigerate

Specimen Stability

Ambient: 8 hours

Refrigerate: 4 days capped

Frozen: 1 month capped (serum). Do not freeze lithium heparin plasma

Laboratory Retention: 72 hours

Test Frequency

Available 24 hours, usual TAT 1 day.

Reference Range

% Free Phenytoin
7 – 13 %

 

Phenytoin Free Lvl
1.0 – 2.0 mcg/mL

 

Phenytoin Total Lvl

10.0 – 20.0 mcg/mL

 

Laboratory Critical Values Table

Performing Department

Chemistry

Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI

Methodology

Kinetic Interaction of Micro particles in a Solution (KIMS)

CPT

80185, 80186

CDM Code

3018018501, 3018018601

Epic Test ID

1230101037

LOINC

Phenytoin Total Lvl: 3968-5

Phenytoin Free Lvl: 3969-3

% Bound Phenytoin: Pending

% Free Phenytoin: 10548-6

Mayo Access Code

SHO8327

Reviewed Date

3/7/2024

Updated Date

3/15/2024 - Reference Range