Fentanyl+Norfentanyl:PrThr:Pt:Ser/Plas:Ord:Confirm
fentanyl+norfentanyl:prthr:pt:ser/plas:ord:confirm
fentaNYL+Norfentanyl [Presence] in Serum or Plasma by Confirmatory method
fentanyl+norfentanyl [presence] in serum or plasma by confirmatory method