Detection of pancreatic steatorrhea by oral pancreatic function tests

Abstract

Pancreolauryl and NBT-PABA tests were performed in urine of 54 patients with exocrine pancreatic insufficiency and, additionally, in serum of 29 of these patients. All patients underwent a secretin-pancreozymin test and a 72-hr fecal fat analysis. Pancreatic steatorrhea occurred (with only three exceptions) when the pancreolauryl test revealed a T/C ratio [recovery of the fluorescein of the test (T) and the control (C) day] of less than 10, or when serum fluorescein concentrations were below 0.5 microgram/ml. The NBT-PABA test also showed a negative correlation between urinary PABA excretion or serum PABA concentration and fecal fat excretion, but there was no diagnostically useful cutoff limit indicating decompensation of exocrine pancreatic insufficiency. These findings indicate that the pancreolauryl test may facilitate clinical evaluation of patients with chronic pancreatitis by simultaneously assessing exocrine pancreatic insufficiency as a cause and predicting pancreatic steatorrhea as a sequel of maldigestion. In clinical practice, the pancreolauryl test can be used as a parameter for deciding whether to initiate pancreatic enzyme substitution if direct pancreatic function tests and fecal fat analysis are not available.

Fecal Fat Concentration in the Screening of Steatorrhea

“…We suggest that the fecal fat concentration should not be used in the differential diagnosis, but to detect the presence of a relevant steatorrhea. The diagnostic capacity for digestive insufficiency of this simple measurement in patients with CP compares favorably with that of the oral pancreatic tests [9] which are more complex and time-consuming. A possible alternative could only be represented by fecal chymotrypsin.…”

“…Its quantitation is an essential parameter mainly in the follow-up of the affected pa tients in order to know when nutritional defi cits develop and also to monitor need and efficacy of therapeutic interventions [1], In fact, steatorrhea is a late finding in the natural history of the diseases possibly causing malab sorption [2,3], and therefore its measurement is not sensitive enough to be considered a diagnostic tool [4], The fat malabsorption is usually quantitated by the fat balance. This requires the collection of all stools produced during a long enough period, a diet of known fat content, the stool homogenization and the use of a complex and unpleasant titrimctric assay [5], The indirect tests of fat malabsorp tion so far suggested (l4C-triolcin measure ment in stools [6] and in the expired air [7], tubeless pancreatic function tests [8,9]) are too complex, time-consuming, and not accu rate enough [10. 11].…”

Appropriate pancreatic function tests and indication for pancreatic enzyme therapy following surgical procedures on the pancreas

“…For the bentiromide test such a correlation has not been established [57]. Similar studies for chymotrypsin and elastase-1 are not available.…”

“…Performance of the test is not standardized and each center has its own procedure and normal values. For general clinical investigations, nonabsorbable markers such as polyethylene glycol, or 57 Co-labelled vitamin B 12 or calculating loss of duodenal contents, are not necessary [30,31]. If amylase output is relatively higher than lipase or trypsin output this is not due to postoperative improvement, but to addition of salivary isoamylase [32], following Billroth-II resection the duodenal tube has to be placed into the afferent loop.…”

Tests of Exocrine Pancreatic Function

“…Conversely, false negative results can occur in antibiotic therapy because of inhibition of normal bacterial breakdown of chymotrypsin. 20,22 The reliability of the test in severe exocrine dysfunction, and the ease of random sample collection (as opposed to timed urine collections), make the stool chymotrypsin test particularly useful in the assessment of cystic fibrosis children: 100% sensitivity and 97% specificity have been reported." There is a strong correlation between faecal chymotrypsin concentrations and age in the first 2 years of life, with mean values ranging ftom 73 /Lg/g stool wet weight at 1-7 days of age to 198 /Lg/g at 3-6 months and 567 /Lg/g at 14-18 months."…”