Test Code PTN Phenytoin (Dilantin®), Plasma or Serum
Additional Codes
St. Luke's Compendium Code (Iatric): L315.0235
Performing Laboratory
St. Lukes Hospital Laboratory
Methodology
Particle enhanced turbidimetric inhibition immunoassay (PETINIA) technique.
Specimen Requirements
Separated specimens may be stored for up to 24 hours at room temperature or for up to 2 days at 2 - 8°C
Submit only 1 of the following specimens:
Plasma
Draw blood in a green-top (lithium heparin) plasma gel tube(s) 30 minutes prior to next dose for trough level. Spin down and send 1 mL of lithium heparin plasma refrigerated.
Note: 1. Indicate date and time of last dose and plasma on request form.
2. Label specimen appropriately (date and time of last dose and plasma).
Serum
Draw blood in a serum gel tube(s) 30 minutes prior to next dose for trough level. Spin down and send 1 mL of serum refrigerated.
Note: 1. Indicate date and time of last dose and serum on request form.
2. Label specimen appropriately (date and time of last dose and serum).
Unspun specimens must be transported at ambient temperature and arrive to the laboratory within one hour of draw.
Reference Values
Therapeutic concentration: 10-20 mcg/mL
Critical value (automatic call-back): >35 mcg/mL
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
CPT: 80185
LOINC: 35632-9