Fecal fat microscopy. Acceptable predictive value in screening for steatorrhea.
Fecal fat droplet count was compared with Van de Kamer chemical determination of fecal fat in 41 adults (24 excreting fat in excess of 6 gm./24 hr.) in an aliquot of a 36-hour fecal collection. Predictability of the droplet count was confirmed by a positive correlation (P less than 0.01) between chemical fat and droplets when serially diluting stool containing high fat. The droplet count separated normal and abnormal fat excretors with a probability similar to the chemical analysis (P less than 0.001). The droplet count correlated with the chemical analysis (P less than 0.01) and using a calibration curve it predicted the amount of fat in the microscopic counting space (P less than 0.01). Improved standardization (dilution of stool 1:1 with Sudan-acetic acid, counting in a hemacytometer, microscopy of heated specimen) can easily be adopted by a bedside laboratory. Microscopy in an aliquot of stool homogenate collected over 24 hours is preferable over microscopy from a random stool specimen.