Dk green heparin (Li or Na), no gel
Immediately following collection, mix sample thoroughly by gently inverting 8 - 10, times to prevent clotting
Frozen (strict) - 14 days
Refrigerated - NO
Ambient - NO
Gel-barrier tubes are not recommended
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
5.0 - 20.0 ng/mL
Peak levels occur at 1-3 hours post dose
Trough levels are often not detectable