Observation:SpGrav:Pt:Plr fld:Qn:Refractometry
observation:spgrav:pt:plr fld:qn:refractometry
Observation:SpGrav:To identify measures at a point in time:Pleural fluid (thoracentesis fld):Quantitative:Refractometry
observation:spgrav:to identify measures at a point in time:pleural fluid (thoracentesis fld):quantitative:refractometry