Markers for faecal fat estimation in monitoring steatorrhoea in cystic fibrosis.

Polyethylene glycol (PEG) 4000 is one of numerous substances used as non-absorbable markers to correct for variable faecal output when assessing daily faecal losses of nutrients. The introduction of enteric coated micro-encapsulated pancreatic enzyme (EMPE) preparations has greatly improved the control of fat malabsorption in cystic fibrosis and chronic pancreatitis patients. Unfortunately, these enzyme preparations contain significant quantities of PEG 4000 or polyvinyl pyrrolidine (PVP) as components of the enteric coating and thus PEG 4000 cannot be used either as a faecal marker, or in intubation studies, if these enzyme preparations are being used.