Steatorrhea cannot be excluded where there is a fecal weight below 0.200 kg per day and a high fecal consistency

We surveyed one year's results of fecal fat (feces alifatic carboxylates) analyses, which are used in the diagnosis of malabsorption (steatorrhea), by calculating the relationship between fecal fat, fecal weight (fecal mass excretion rate) and fecal consistency (in terms of the volume of water added to a fecal mass so that it can be aspirated into a pipette). N=203 analyses from 191 patients. Reference range for fecal fat: 0-24 mmol/24 h. Linear regression and correlation analyses showed an inverse correlation between fecal weight and fecal consistency and a positive correlation between fecal weight and fecal fat. Our results confirmed earlier findings in the literature that approximately 17% of steatorrheic specimens would be missed if a fecal weight below 0.200 kg/24 h was used to exclude further fecal fat analysis. Fewer steatorrheic specimens would be missed if a lower fecal weight were used: 7% at 0.180 kg/24 h, 3% at 0.140 kg/24 h and 0% at 0.120 kg/24 h. There was no correlation between fecal fat and consistency. The mean volume of added water was not different in normal and steatorrheic feces. The fat content could be predicted as normal only in the seven specimens (3.5% (1-7%)) that had more than 3.8 L/kg water added. Thus, an abnormal fecal fat content cannot reliably be excluded, in a routine setting, on the basis of a fecal weight below 0.200 kg/24 h and a high fecal consistency.