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HelpTest Code PTNT Phenytoin (Dilantin), Total, Plasma or Serum
Additional Codes
LAB31
Methodology
Used for therapeutic drug monitoring. Phenytoin is the most widely used anticonvulsant. It is effective against grand mal and the generalized spread of seizures with focal origin.
Performing Laboratory
St. Mary's Regional Medical Center-Chemistry
CPT: 80185
Specimen Requirements
Submit one of the following:
Plasma
Container/Tube: Light green-top (lithium heparin) tube
Specimen: 1 mL of lithium heparin plasma
Transport Temperature: Ambient
Collection Instructions: Draw specimen just prior to administration of next dose for therapeutic response.
Note: 1. Indicate plasma.
2. Label specimen appropriately (plasma).
Serum
Container/Tube: Plain red top or gold serum gel tube
Specimen: 1 mL of serum
Transport Temperature: Ambient
Collection Instructions: Draw specimen just prior to administration of next dose for therapeutic response.
Note: 1. Indicate plasma.
2. Label specimen appropriately (serum).
Reference Values
Therapeutic concentration: 10-20 mcg/mL
Potentially toxic concentration: >30 mcg/mL
Call criteria (automatic call-back): >25 mcg/mL
Day(s) Test Set Up
Monday through Sunday