Test Details
Methodology
Immunoassay (IA); ultrafiltration
Result Turnaround Time
3 - 7 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Therapeutic drug management
Specimen Requirements
Specimen
Serum or plasma
Volume
3 mL
Minimum Volume
1 mL
Container
Red-top tube or green-top (heparin) tube. Gel-barrier tubes are not recommended.
Collection Instructions
Serum or plasma should be separated from cells within two hours of venipuncture. Submit serum or plasma in a plastic transport tube.
Reference Range
6.0−20.0 µg/mL
Storage Instructions
Submission/transport (<3 days): Room temperature. For storage beyond three days, specimen should be refrigerated or frozen.
Patient Preparation
Trough levels are most reproducible.
Causes for Rejection
Gel-barrier tubes