The steatocrit: a simple method for monitoring fat malabsorption in patients with cystic fibrosis.

Steatocrit was determined through microcentrifugation of fecal homogenate from 110 pediatric controls and 107 patients with cystic fibrosis (CF). For 74 CF patients, steatocrit was determined in the same fecal material collected to determine a fat balance. In controls, steatocrit value was 0.7 +/- 1.0%, which was significantly lower than values found in CF patients with a coefficient of fat excretion less than 10% of intake (1.7 +/- 1.2%). Significantly increased values were found in CF patients with a coefficient of fat excretion ranging between 10 and 25% of intake (4.7 +/- 1.7%) and in those whose coefficient of fat excretion was greater than 25% of intake (11.3 +/- 4.3%). In the 74 CF patients, steatocrit was directly correlated to the coefficient of fat excretion (r = 0.93; P less than 0.001). We performed steatocrit several times in the course of the 1st year of life in 33 infants with CF diagnosed by means of CF screening. Values obtained at the time of diagnosis, before starting enzymatic therapy, were relatively high; they showed a progressive decrease when, using steatocrit as a guide, the dose of pancreatic enzymes had been increased. The normalization of steatocrit values was accompanied by a better growth rate in the majority of these infants, confirming the importance of an optimal early correction of pancreatic insufficiency. We propose that this simple semiquantitative test can be usefully performed for the frequent monitoring of fat absorption and for checking the response to enzymatic therapy in patients with CF.