Creatinine.plr fld/Creatinine.serum:RelRto:Pt:Ser/Plas+Plr fld:Qn
creatinine.plr fld/creatinine.serum:relrto:pt:ser/plas+plr fld:qn
Creatinine in pleural fluid/Creatinine in serum (S/P+Pleur fld) [Relative ratio]
creatinine in pleural fluid/creatinine in serum (s/p+pleur fld) [relative ratio]