Specimen Requirements

Submit only 1 of the following specimens:
 
Plasma
Draw blood in a green-top (sodium heparin) tube(s) 8 to 12 hours after last dose (trough specimen). (Green-top [lithium heparin] tube is not acceptable.) Spin down and send 0.5 mL of plasma. Peak plasma concentrations do not correlate with symptoms.

Note:  1. Indicate plasma on request form.
2. Label specimen appropriately (plasma).

Serum

Draw blood in a plain, red-top tube(s) or serum gel tube(s) 8 to 12 hours after last dose (trough specimen). Spin down and send 0.5 mL of serum. Peak serum concentrations do not correlate with symptoms.

Note:  1. Indicate serum on request form.
2. Label specimen appropriately (serum).