Therapeutic drug management
Trough levels are most reproducible
Dk green heparin (Li or Na), no gel
Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times, to prevent clotting
Refrigerated (preferred)
Frozen
Ambient: <3 days
Gel-barrier tubes are not recommended
Immunoassay (IA)
4.0 - 16.0 µg/mL