Urea^post dialysis/pre dialysis:SRto:Pt:Ser/Plas:Qn
urea^post dialysis/pre dialysis:srto:pt:ser/plas:qn
Urea [Molar ratio] in Serum or Plasma --post dialysis/pre dialysis
urea [molar ratio] in serum or plasma --post dialysis/pre dialysis