Urea nitrogen^post dialysis/pre dialysis:MRto:Pt:Ser/Plas:Qn
urea nitrogen^post dialysis/pre dialysis:mrto:pt:ser/plas:qn
Urea nitrogen [Mass ratio] in Serum or Plasma--post dialysis/pre dialysis
urea nitrogen [mass ratio] in serum or plasma--post dialysis/pre dialysis