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Laboratory Test Directory

Phenytoin

Components

Name Method Department Units
Phenytoin Chemiluminescent Microparticle Immunoassay (CMIA)
Core Lab, Endocrinology ug/mL

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume
Preferred

Green tube (Lithium heparin), No Gel

3 mL 3 mL
Alternate

Red tube, (no anticoagulant), No Gel

Micro sample tube 1 mL
Alternate

Green tube (Lithium heparin), No Gel

Micro sample tube 1 mL
Alternate

Green tube (Sodium heparin), No Gel

3 mL 3 mL
Alternate

Red tube, (no anticoagulant), No Gel

3 mL 3 mL
Stability

Room temperature - 48 hour(s)
Refrigerated - 48 hour(s)

Specimen Preparation

  • Mix heparin tube by gentle inversion immediately after collection
  • Do not freeze

Plasma Spun, Serum Spun

Container Type Container Size Specimen Volume
Preferred

Green tube (Lithium heparin), No Gel

3 mL 3 mL
Alternate

Green tube (Lithium heparin), No Gel

Micro sample tube 1 mL
Alternate

Green tube (Sodium heparin), No Gel

3 mL 3 mL
Alternate

Red tube, (no anticoagulant), No Gel

3 mL 3 mL
Alternate

Red tube, (no anticoagulant), No Gel

Micro sample tube 1 mL
Stability

Room temperature - 48 hour(s)
Refrigerated - 8 day(s)
Frozen - 5 month(s)

Specimen Preparation

  • Mix heparin tube by gentle inversion immediately after collection

Reasons for Rejection

  • Collected in tube with gel separator
  • Frozen whole blood
  • Gross hemolysis
  • Gross icterus
  • Gross lipemia
  • Wrong collection tube
  • Wrong type of specimen

Comments

Note exact time of collection. Assay will also adequately measure phosphenytoin (Fosphenytoin) as phosphenytoin is a prodrug of phenytoin and converts to the active metabolite, phenytoin, within 30 minutes of administering.

CPT Code

  • 80185