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
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