Specimen Requirements

Container/Tube:

Preferred: Green-top (lithium heparin) tube

Acceptable: Gold-top serum gel tube or plain, red-top tube, EDTA plasma
Minimum Specimen Volume:  14.6 µL plus dead space of plasma or serum

Stability: 15-25 °C for 3 days, 2 – 8 °C and analyzed within 7 days. For longer storage, samples may be frozen at -20 °C for up to one month.

Note:  Venipuncture should occur prior to sulfasalazine and/or sulfapyridine administration due to the potential for falsely depressed results.