Laboratory Medicine

Test catalogue

Phenytoin
Test Name Phenytoin (Dilantin)
Specimen Type/Requirements Container Type = 1 Red Top Minimum Testing Volume = 0.5 mL serum Tube must fill to at least ½ or greater of its vacuum capacity
Specimen Handling Collection Instructions: Serum collected in red top vacutainer (without gel separator). The sample is collected before administration of the next dose or must be collected at the same time in relation to the dose administration to obtain comparable results. Write your initials, date and time of collection on the collection label or requisition. Special Instructions: Separate samples from cells as soon as possible. Repeated freezing and thawing of samples should be avoided Rejection Criteria: Gel separator, grossly hemolyzed and icteric samples, Unlabeled or Not Sufficient Quantity Samples will be rejected. Stability: Stable at room temperature for 7 days, refrigerated for 14 days, and frozen for 30 days. Transportation: Send sample to core lab as soon as possible.
Required Documentation
Turnaround Time (TAT) STAT: 1 hour Routine: 2 hours	Test Utilization
Reference Value Therapeutic Interval: 0 – 2 months: 24 – 55 umol/L 3 months and older: 40 – 80 umol/L Critical Values: 0 – 2 months: >55 umol/L 3 months and older: > 80 umol/L
Test Code LAB31	Methodology KIMS Immunoassay
Testing Location SMH-Biochemistry	Other Information Last Updated: June 22, 2026

Phenytoin

Test Name

Phenytoin (Dilantin)

Specimen Type/Requirements

Container Type = 1 Red Top

Minimum Testing Volume = 0.5 mL serum

Tube must fill to at least ½ or greater of its vacuum capacity

Specimen Handling

Collection Instructions: Serum collected in red top vacutainer (without gel separator). The sample is collected before administration of the next dose or must be collected at the same time in relation to the dose administration to obtain comparable results. Write your initials, date and time of collection on the collection label or requisition.

Special Instructions: Separate samples from cells as soon as possible. Repeated freezing and thawing of samples should be avoided

Rejection Criteria: Gel separator, grossly hemolyzed and icteric samples, Unlabeled or Not Sufficient Quantity Samples will be rejected.

Stability: Stable at room temperature for 7 days, refrigerated for 14 days, and frozen for 30 days.

Transportation: Send sample to core lab as soon as possible.

Required Documentation

Turnaround Time (TAT)

STAT: 1 hour

Routine: 2 hours

Test Utilization

Reference Value

Therapeutic Interval:

0 – 2 months: 24 – 55 umol/L

3 months and older: 40 – 80 umol/L

Critical Values:

0 – 2 months: >55 umol/L

3 months and older: > 80 umol/L

Test Code

LAB31

Methodology

KIMS Immunoassay

Testing Location

SMH-Biochemistry

Other Information

Last Updated: June 22, 2026