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Test Code PHENY Phenytoin, Total, Plasma or Serum

Additional Codes

LAB31

Important Notes

Phenytoin, Total, Plasma or Serum test is for medical use only.

Collection Method

Venous collection

Minimum Volume

0.5ml

Container

Lt Green / Plasma Separator / Lithium Heparin

Acceptable Specimens

Serum:

  • Gold Top SST
  • Red Top

Plasma:

  • Light Geen Top (lithium heparin)

Reference or Target Ranges

10-20 µg/mL

 

Peak: 4 -5 hours post oral dose

Trough: Just prior to next dose

Reportable Units

µg/mL

Critical Value

≥ 30 µg/mL

Reasons for Rejection

Hemolysis Threshold 1000 mg/dL
Icterus Threshold 50 mg/dL
Lipemia Threshold 800 mg/dL
Other QNS, contaminated, improperly Labeled, improper specimen type

Specimen Stability

Ambient 4 days
Refrigerated (4°C to 8°C) 4 days 
Frozen(-40°C to 0°C) 2 months

Performance Information

Days and Time Performed 24/7
Expected Turn Around Time

STAT: 1 hour

Routine: 4 hours
Stat Availability Yes
Performing Bench CPH Chemistry
Methodology/Method Description Roche Cobas

CPT Codes

80186

Last review/edit date

2025