Serum lipase after secretin stimulation detects mild pancreatic involvement in cystic fibrosis.

BACKGROUND: The assessment of severe pancreatic insufficiency in cystic fibrosis (CF) is not a diagnostic problem. However, identification of mild cases remains a challenge. The aim of this study was to assess the ability of serum lipase after secretin stimulation to identify mild pancreatic insufficiency in patients with CF. MATERIAL AND METHODS: Thirty patients with CF and pancreatic insufficiency (CF-PI) and 30 patients with CF and pancreatic sufficiency (CF-PS) were studied. Thirty healthy subjects with no known gastrointestinal disease served as controls. In all subjects, fecal fat excretion, fecal elastase-1 (E1) concentration and basal and secretin-stimulated serum lipase concentration were measured. RESULTS: All patients with CF-PI and 3 with CF-PS had abnormally low fecal E1 concentrations. The remaining 27 CF-PS patients and all controls had normal values. Basal and post-stimulation lipase levels were extremely low in patients with CF-PI. Mean basal and poststimulation serum lipase concentrations were significantly higher in CF-PS who had normal fecal E1 concentrations but were still below those of controls (P < 0.001). Among the 27 CF-PS patients with normal fecal elastase, high basal and poststimulation lipase values were found in 6 and 17 patients respectively. CONCLUSION: In patients with CF-PS who have normal fecal elastase-1 concentration, the measurement of basal or secretin-stimulated lipase levels might be helpful in identifying the progression of the destructive process in the pancreas.

[Comparison of faecal lipase test and faecal elastase-1 test in the assessment of exocrine pancreatic function in cystic fibrosis]. / Porównanie przydatnosci oznaczania elastazy-1 i lipazy w stolcu w ocenie funkcji zewnatrzwydzielniczej trzustki u chorych na muskowiscydoze.

OBJECTIVE: In pediatric patients, indirect tests are preferred because of their less invasive character. Among those, faecal elastase-1 test has so far been shown been shown to have the highest sensitivity and specificity. However, the role of the faecal lipase test in the diagnostic work up for pancreatic insufficiency in cystic fibrosis (CF) patients has not been defined. Therefore, the aim of the present study was to compare the sensitivity and the specificity of faecal lipase test to the faecal elastase-1 test in the assessment of exocrine pancreatic function. MATERIAL AND METHODS: 63 CF patients and 95 healthy subjects (HS) were evaluated. In all subjects, faecal elastase-1 concentration (ELISA) and lipase activity (ELISA) were measured. In 50 HS, sample-to-sample (n=3) variation from the same stool and day-to-day variation from three consecutive stools were determined twice. The presence of pancreatic insufficiency patients was documented in 55 pancreatic insufficient CF patients by the determination of faecal fat excretion and in 12 pancreatic sufficient patients by the direct test. The sensitivity and specificity of the faecal elastase-1 test and faecal lipase test were compared. RESULTS: The sample-to-sample variation (mean + SEM: 13.2+1.2% vs. 23.4+2.2%) and day-to-day variation (mean + SEM: 16.3+1.2% vs. 32.5+2.6%) were significantly lower (p<0.0001) for elastase-1 determinations than for lipase measurements. With the cut-off levels giving the same specificity for both tests (95.8%), the sensitivity of faecal elastase-1 test (87.3%) was significantly higher (p<0.04) than that of faecal lipase test (77.8%). IN CONCLUSION: Faecal lipase test is less useful in the assessment of exocrine pancreatic function sensitive than faecal elastase-1 test.

Longitudinal follow-up of exocrine pancreatic function in pancreatic sufficient cystic fibrosis patients using the fecal elastase-1 test.

BACKGROUND: A progressive decline in pancreatic function is possible in cystic fibrosis (CF) patients with exocrine pancreatic sufficiency. The secretin-cholecystokinin test is invasive and not acceptable as a repeatable procedure for children. Steatorrhea, conversely, has low sensitivity. Therefore, the aim of the present study was to evaluate the usefulness of the noninvasive fecal elastase-1 (E1) test for the longitudinal assessment of exocrine pancreatic function (EPF) in pancreatic-sufficient (PS) CF patients. METHODS: One hundred eighty-four CF patients were included in the study. In all subjects, E1 concentrations and fecal fat excretion were measured. PS patients were followed for 5 years. RESULTS: At the beginning of the study, 35 (19.0%) CF patients were PS, and 32 (17.4%) had normal E1 concentrations. Longitudinal measurements of E1 concentrations in PS patients with CF demonstrated stable enzyme output in 27 and gradual decrease in 8. The decrease was rapid in five infant patients and gradual in three older patients. The decrease of E1 concentrations preceded the appearance of steatorrhea in all eight subjects. CONCLUSIONS: The decline of EPF in patients with CF appears more frequently during the first months and years of life. However, late PS to pancreatic-insufficient (PI) conversion is also possible. The appearance of maldigestion is preceded by the decrease of fecal E1 concentration. Thus, the fecal E1 test is a helpful screening tool for the longitudinal assessment of declining EPF in PS patients with CF to demonstrate pancreatic deterioration. In suspected patients, fecal fat excretion should be assessed.

Fecal elastase-1 is superior to fecal chymotrypsin in the assessment of pancreatic involvement in cystic fibrosis.

OBJECTIVE: Exocrine pancreatic function in patients with cystic fibrosis (CF) can be evaluated by direct and indirect tests. In pediatric patients, indirect tests are preferred because of their less invasive character, especially in CF patients with respiratory disease. Fecal tests are noninvasive and have been shown to have a high sensitivity and specificity. However, there is no comparative study in CF patients. Therefore, the aim of the present study was to compare the sensitivity and the specificity of the fecal elastase-1 (E1) test with the fecal chymotrypsin (ChT) test in a large cohort of CF patients and healthy subjects (HS). DESIGN: One hundred twenty-three CF patients and 105 HS were evaluated. In all subjects, E1 concentration and ChT activity were measured. In the CF group, fecal fat excretion was also determined. The sensitivity and specificity of the fecal E1 test and ChT test were compared. RESULTS: With a cutoff level of 3 U/g, ChT specificity in HS was similar to that of E1, but E1 sensitivity in CF patients was significantly higher (90.2% vs 81.3%). With a cutoff level of 6 U/g, ChT and E1 sensitivity in CF patients was identical, but E1 specificity in HS was again significantly higher (98.1% vs 90.5%). In all CF patients with severe steatorrhea (>15 g/d), E1 concentrations were abnormal and ChT activity was lower than 3 U/g. In contrast, in pancreatic-sufficient patients and patients with mild steatorrhea (< or =15 g/d), the E1 sensitivity was significantly higher compared with ChT (69.2% vs 41.0%). CONCLUSIONS: The fecal E1 test is superior to fecal ChT determination in the assessment of CF pancreatic involvement in pancreatic-sufficient patients and those patients with mild steatorrhea.

Fecal elastase-1 cut-off levels in the assessment of exocrine pancreatic function in cystic fibrosis.

BACKGROUND: Fecal elastase-1 (E1) test is a sensitive and specific indirect test. However, there are few data on the best cut-off level in the assessment of exocrine pancreatic function in cystic fibrosis (CF). MATERIAL AND METHODS: In 725 CF patients and 243 healthy subjects (HS) from Greece, Russia, Poland and the United Kingdom, E1 concentrations were measured. The best cut-off levels for the discrimination between CF and HS (for whole group as well as for individual countries) were calculated. RESULTS: The best cut-off level for the differentiation between CF pancreatic insufficiency and normal pancreatic function in HS was found to be 184 microg/g of feces. However, some inter-country differences were stated. E1 concentrations in the UK subgroup were significantly lower than those found in Polish and Russian CF patients. E1 concentrations in Greek patients were significantly higher than in the other countries. However, E1 concentrations in Delta F508 homozygotes were very similar in all studied subgroups. IN CONCLUSION: In clinical practice, instead of a single best cut-off level for the E1 test, we suggest using a range of values (160-200 microg/g). The presence of different best cut-off levels within countries is a practical consequence of the different distribution of pancreatic function.