Comparison of fecal elastase-1 determination with the secretin-cholecystokinin test in patients with cystic fibrosis

Pancreas and pancreatitis: Exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI) is highly prevalent among individuals with cystic fibrosis (CF). Individuals diagnosed with EPI are often labeled as having "pancreas insufficient cystic fibrosis (PI-CF)" while those with normal exocrine function are labeled as "pancreas sufficient CF (PS-CF)." This diagnosis of EPI relies on clinical and laboratory features and management involves consumption of pancreas enzyme replacement therapy. In this review, we discuss the nuances of diagnosis and management of EPI in CF. We also present emerging evidence on the effects of CFTR modulating agents on the management of EPI, and speculate that these medications may lead to greater heterogeneity in management of EPI in CF moving forward.

Alterations in exocrine pancreatic function after acute pancreatitis

Exocrine pancreatic dysfunction (EPD) is a malabsorptive complication of pancreatic disorders that can lead to a host of symptoms ranging from flatulence to diarrhea and contribute to weight loss and metabolic bone disease. It is increasingly recognized to occur after acute pancreatitis (AP), including episodes with mild severity. The risk of developing EPD after AP is influenced by a range of factors, including the degree of acinar cell destruction and inflammation during AP, and persistent structural derangements following AP. In this article, we discuss the epidemiology, pathophysiology, and clinical management of EPD after AP while highlighting key knowledge gaps.

Inherited causes of exocrine pancreatic insufficiency in pediatric patients: clinical presentation and laboratory testing

Pediatric patients with exocrine pancreatic insufficiency (EPI) have symptoms that include abdominal pain, weight loss or poor weight gain, malnutrition, and steatorrhea. This condition can be present at birth or develop during childhood for certain genetic disorders. Cystic fibrosis (CF) is the most prevalent disorder in which patients are screened for EPI; other disorders also are associated with pancreatic dysfunction, such as hereditary pancreatitis, Pearson syndrome, and Shwachman-Diamond syndrome. Understanding the clinical presentation and proposed pathophysiology of the pancreatic dysfunction of these disorders aids in diagnosis and treatment. Testing pancreatic function is challenging. Directly testing aspirates produced from the pancreas after stimulation is considered the gold standard, but the procedures are not standardized or widely available. Instead, indirect tests are often used in diagnosis and monitoring. Although indirect tests are more widely available and easier to perform, they have inherent limitations due to a lack of sensitivity and/or specificity for EPI.

Staging exocrine pancreatic dysfunction

Digestive capacity of the gastrointestinal tract, largely but not wholly, depends on exocrine pancreatic function to achieve near complete digestion and absorption of ingested food. Coefficient of fat absorption (CFA), the proportion of ingested fat absorbed (normal >93%), reflects digestive capacity. Exocrine pancreatic insufficiency (EPI) is the state of insufficient digestive capacity (CFA <93%) caused by severe loss of pancreatic exocrine function despite variable compensation by upregulation of extra-pancreatic lipolysis. Fecal elastase 1 (FE1) level is the most widely used, though imperfect, non-invasive test of pancreatic enzyme output. Decline in pancreas enzyme output, or pancreatic exocrine dysfunction (EPD), has a variable correlation with measurable decline in CFA. EPI results in steatorrhea, weight loss and nutrient deficiency, which are mitigated by pancreatic enzyme replacement therapy (PERT). We propose a staging system for EPD, based on measurement of fecal elastase (FE1) and, if necessary, CFA and serum fat-soluble vitamin levels. In Stage I (Mild) EPD, FE1 is 100-200 mcg/gm; if steatorrhea is present, non-pancreatic causes are likely. In Stage II (Moderate) EPD), FE1 is < 100 mcg/gm without clinical and/or laboratory evidence of steatorrhea. In Stage III, there are marked reductions in FE1 and CFA, but vitamin levels remain normal (Severe EPD or EPI without nutritional deficiency). In Stage IV all parameters are abnormal (Severe EPD or EPI with nutritional deficiency). EPD stages I and II are pancreas sufficient and PERT may not be the best or first approach in management of early-stage disease; it needs further study to determine clinical utility. The term EPI refers strictly to EPD Stages III and IV which should be treated with PERT, with Stage IV requiring micronutrient supplementation as well.

Assessment of exocrine pancreatic function in children and adolescents with direct and indirect testing

The exocrine pancreas plays an important role in digestion. Understanding of the physiology and regulation of exocrine function provides insight into disease processes and basis of functional testing. Specifically, exocrine pancreatic insufficiency (EPI) can cause maldigestion and thus a proper assessment of exocrine pancreatic function is important. There are indirect and direct methods for evaluating pancreatic function. Indirect methods are varied and include stool, serum, urine, and breath tests. Fecal elastase is a commonly used indirect test today. Direct methods involve stimulated release of pancreatic fluid that is collected from the duodenum and analyzed for enzyme activity. The most used direct test today is the endoscopic pancreatic function test. Indirect pancreatic function testing is limited in identifying cases of mild to moderate EPI, and as such in these cases, direct testing has higher sensitivity and specificity in diagnosing EPI. This review provides a comprehensive guide to indirect and direct pancreatic function tests as well as an in-depth look at exocrine pancreatic function including anatomy, physiology, and regulatory mechanisms.

Consensus for the management of pancreatic exocrine insufficiency: UK practical guidelines

INTRODUCTION

Pancreatic exocrine insufficiency is a finding in many conditions, predominantly affecting those with chronic pancreatitis, pancreatic cancer and acute necrotising pancreatitis. Patients with pancreatic exocrine insufficiency can experience gastrointestinal symptoms, maldigestion, malnutrition and adverse effects on quality of life and even survival.There is a need for readily accessible, pragmatic advice for healthcare professionals on the management of pancreatic exocrine insufficiency.

METHODS AND ANALYSIS

A review of the literature was conducted by a multidisciplinary panel of experts in pancreatology, and recommendations for clinical practice were produced and the strength of the evidence graded. Consensus voting by 48 pancreatic specialists from across the UK took place at the 2019 Annual Meeting of the Pancreatic Society of Great Britain and Ireland annual scientific meeting.

RESULTS

Recommendations for clinical practice in the diagnosis, initial management, patient education and long term follow up were developed. All recommendations achieved over 85% consensus and are included within these comprehensive guidelines.

Report on the Short Endoscopic Exocrine Pancreatic Function Test in Children and Young Adults

OBJECTIVES

Endoscopic pancreatic function test (ePFT) has been in use for exocrine function testing since the 1990s. In patients, short ePFT assesses acinar function, unlike the longer version for ductal function in adults. The present study summarizes characteristics of 1913 short ePFTs (S-ePFT) performed at 2 centers since 2001.

METHODS

The main indications in patients presenting at ages infancy to 24.3 years, for the S-ePFT were failure to thrive, weight loss, diarrhea, and abdominal pain with bloating. Secretin was administered as bolus, and 4 aliquots of fluid were collected between 4 and 10 minutes after administration. Amylase, lipase, trypsin, and chymotrypsin activities were measured in the laboratory.

RESULTS

The pH of consecutive samples increased by 0.3 to 0.7. Overall, 36.7% had abnormal S-ePFT with selective amylase deficiency (9.5%) and generalized enzyme deficiency (8.9%) being the most frequent. Retest reproducibility, repeatability, and clinical validity were high. By adding S-ePFT to endoscopy for the suspicion of malabsorption, the abnormal findings increased by 36.9%.

CONCLUSIONS

Short ePFT assesses pancreatic acinar function in a reliable and clinically meaningful way in patients. Diagnostic yield of endoscopy increased substantially albeit with increased sedation time. By S-ePFT ductal function, cytokines and proteomics can also be assessed.

Assessment of Exocrine Pancreatic Function During Endoscopy in Children

This article will review briefly the physiology of pancreatic enzyme secretion and the role of stimulated endoscopic testing for assessing exocrine pancreatic function. Published studies in both the pediatric and adult literature are reviewed. The technique and utility of endoscopic pancreatic function testing as the method of choice in the differential diagnosis of pancreatic disorders in childhood is described. Finally, emerging, clinically useful markers that can be measured in the pancreatic fluid will be described.

Diagnostic Performance of Measurement of Fecal Elastase-1 in Detection of Exocrine Pancreatic Insufficiency: Systematic Review and Meta-analysis

BACKGROUND & AIMS

Tests to quantify fecal levels of chymotrypsin like elastase family member 3 (CELA3 or elastase-1) in feces are widely used to identify patients with exocrine pancreatic insufficiency (EPI). However, the diagnostic accuracy of this test, an ELISA, is not clear. We performed a systematic review and meta-analysis to determine the accuracy of measurement of fecal elastase-1 in detection of EPI.

METHODS

We searched PubMed, Embase, and reference lists for articles through November 2016 describing studies that compared fecal level of elastase-1 with results from a reference standard, direct method (secretin stimulation test), or indirect method (measurement of fecal fat) for detection of EPI. Sensitivity and specificity values were pooled statistically using bivariate diagnostic meta-analysis.

RESULTS

We included total of 428 cases of EPI and 673 individuals without EPI (controls), from 14 studies, in the meta-analysis. The assay for elastase-1, compared to secretin stimulation test, identified patients with pancreatic insufficiency with a pooled sensitivity value of 0.77 (95% CI, 0.58-0.89) and specificity value of 0.88 (95% CI, 0.78-0.93). In an analysis of 345 cases of EPI and 312 controls, from 6 studies, the fecal elastase-1 assay identified patients with EPI with a pooled sensitivity value of 0.96 (95% CI, 0.79-0.99) and specificity value of 0.88 (95% CI, 0.59-0.97), compared to quantitative fecal fat estimation. In patients with low pre-test probability of EPI (5%), the fecal elastase-1 assay would have a false-negative rate of 1.1% and a false-positive rate of 11%, indicating a high yield in ruling out EPI but not in detection of EPI. In contrast, in patients with high pre-test probability of EPI (40%), approximately 10% of patients with EPI would be missed (false negatives).

CONCLUSIONS

In a systematic review and meta-analysis of studies that compared fecal level of elastase-1 for detection of EPI, we found that normal level of elastase-1 (above 200 mcg/g) can rule out EPI in patients with a low probability of this disorder (such as those with irritable bowel syndrome with diarrhea). However, in these patients, an abnormal level of elastase-1 (below 200 mcg/g) has a high false-positive rate.

13C-Mixed Triglyceride Breath Test and Fecal Elastase as an Indirect Pancreatic Function Test in Cystic Fibrosis Infants

BACKGROUND

The 'gold standard' test for the indirect determination of pancreatic function status in infants with cystic fibrosis (CF), the 72-hour fecal fat excretion test, is likely to become obsolete in the near future. Alternative indirect pancreatic function tests with sufficient sensitivity and specificity to determine pancreatic phenotype need further evaluation in CF infants.

OBJECTIVE

Evaluation of the clinical utility of both the noninvasive, nonradioactive C-mixed triglyceride (MTG) breath test and fecal elastase-1 (FE1) in comparison with the 72-hour fecal fat assessment in infants with CF.

METHODS

C-MTG breath test and the monoclonal and polyclonal FE1 assessment in stool was compared with the 72-hour fecal fat assessment in 24 infants with CF. Oral pancreatic enzyme substitution (PERT; if already commenced) was stopped before the tests.

RESULTS

Sensitivity rates between 82% and 100% for CF patients with pancreatic insufficiency assessed by both the C-MTG breath test and the FE1 tests proved to be high and promising. The C-MTG breath test (31%-38%) as well as both FE1 tests assessed by the monoclonal (46%-54%) and the polyclonal (45%) ELISA kits, however, showed unacceptably low-sensitivity rates for the detection of pancreatic-sufficient CF patients in the present study.

CONCLUSIONS

The C-MTG breath test with nondispersive infrared spectroscopy (NDIRS) technique, as well as both FE1 tests, are not alternatives to the fecal fat balance test for the evaluation of pancreatic function in CF infants during the first year of life.

Comparing acid steatocrit and faecal elastase estimations for use in M-ANNHEIM staging for pancreatitis

AIM

To compare two tests for exocrine pancreatic function (EPF) for use in M-ANNHEIM staging for pancreatitis.

METHODS

One hundred and ninety four consecutive patients with acute pancreatitis (AP; n = 13), recurrent acute pancreatitis (RAP; n = 65) and chronic pancreatitis (CP; n = 116) were enrolled. EPF was assessed by faecal elastase-1 (FE-1) estimation and stool fat excretion by the acid steatocrit method. Patients were classified as per M-ANNHEIM stages separately based on the results of the two tests for comparison. Independent Student's t-test, χ² test, Kruskal-Wallis test, Mann-Whitney U test and McNemar's test were used as appropriate.

RESULTS

Sixty-one (52.5%) patients with CP had steatorrhoea when assessed by the acid steatocrit method; 79 (68.1%) with CP had exocrine insufficiency by the FE-1 test (χ² test, P < 0.001). The results of acid steatocrit and FE-1 showed a significant negative correlation (Spearman's rho = -0.376, P < 0.001). A statistically significant difference was seen between the M-ANNHEIM stages as classified separately by acid steatocrit and the FE-1. Thirteen (6.7%), 87 (44.8%), 89 (45.8%) and 5 (2.5%) patients were placed in M-ANNHEIM stages 0, I, II, and III respectively, with the use of acid steatocrit as against 13 (6.7%), 85 (43.8%), 75 (38.6%), and 21 (10.8%) respectively by FE-1 in stages 0, I, II, and III thereby altering the stage in 28 (14.4%) patients (P < 0.001, McNemar's test).

CONCLUSION

FE-1 estimation performed better than the acid steatocrit test for use in the staging of pancreatitis by the M-ANNHEIM classification since it diagnosed a higher proportion of patients with exocrine insufficiency.

Potential for Screening for Pancreatic Exocrine Insufficiency Using the Fecal Elastase-1 Test

The early diagnosis of pancreatic exocrine insufficiency (PEI) is hindered because many of the functional diagnostic techniques used are expensive and require specialized facilities, which prevent their widespread availability. We have reviewed current evidence in order to compare the utility of these functional diagnostic techniques with the fecal elastase-1 (FE-1) test in the following three scenarios: screening for PEI in patients presenting with symptoms suggestive of pancreatic disease, such as abdominal pain or diarrhea; determining the presence of PEI in patients with an established diagnosis of pancreatic disease, such as chronic pancreatitis or cystic fibrosis; determining exocrine status in disorders not commonly tested for PEI, but which have a known association with this disorder. Evidence suggests the FE-1 test is reliable for the evaluation of pancreatic function in many pancreatic and non-pancreatic disorders. It is non-invasive, is less time-consuming, and is unaffected by pancreatic enzyme replacement therapy. Although it cannot be considered the gold-standard method for the functional diagnosis of PEI, the advantages of the FE-1 test make it a very appropriate test for screening patients who may be at risk of this disorder.

Secretin-stimulated MRI assessment of exocrine pancreatic function in patients with cystic fibrosis and healthy controls

PURPOSE

Secretin-stimulated magnetic resonance imaging (s-MRI) and pancreatic diffusion weighted imaging (DWI) are novel non-invasive imaging techniques for assessment of exocrine pancreatic insufficiency (EPI). The aim was to validate s-MRI assessed pancreatic secreted volume using novel semi-automatic quantification software, and to assess the ability of s-MRI with DWI to diagnose EPI in patients with cystic fibrosis (CF).

METHODS

s-MRI and DWI was performed in 19 patients with CF (median age 21 years; range 16-56; eight men) and in 10 healthy controls (HC) (median age 46 years; range 20-65; four men). Sequential coronal T2-weighted images covering the duodenum and small bowel and axial DWI were acquired before and 1, 5, 9, and 13 min after secretin stimulation. A short endoscopic secretin test was used as reference method for EPI.

RESULTS

CF patients with EPI had lower apparent diffusion coefficient before secretin in the pancreatic head (P < 0.001) and lower secreted bowel fluid volumes (P = 0.035) compared to HC and CF patients without EPI. ROC curve analyses identified that secreted fluid volume after 13 min yielded the highest diagnostic accuracy for diagnosing EPI (AUC 0.93; 95% CI [0.80-1.00]).

CONCLUSION

Pancreatic s-MRI is useful for the assessment of exocrine pancreatic function with high diagnostic accuracy for the diagnosis of EPI in CF.

Diagnostic Accuracy of a Short Endoscopic Secretin Test in Patients With Cystic Fibrosis

OBJECTIVE

Short endoscopic secretin tests for exocrine pancreatic function are not properly evaluated in cystic fibrosis (CF).

METHODS

Patients with CF and healthy controls (HCs) underwent endoscopic collection of duodenal juice between 30 and 45 minutes after secretin stimulation. Duodenal juice was analyzed for HCO3 concentration and pancreatic enzyme activities. Stool was analyzed for fecal elastase.

RESULTS

Thirty-one patients with CF and 25 HCs were tested. Patients were classified as exocrine pancreatic sufficient (n = 13) or insufficient (n = 18). Both bicarbonate concentrations and enzyme activities in duodenal juice differentiated patients with CFI from patients with CFS and HC (P < 0.001). The population displays strong correlation between severe CF genotype in both alleles and pancreatic insufficient phenotype (P < 0.001).

CONCLUSIONS

Pancreatic exocrine insufficient CF patients could be differentiated from exocrine sufficient patients and HCs using short endoscopic secretin test.

ESPGHAN and NASPGHAN Report on the Assessment of Exocrine Pancreatic Function and Pancreatitis in Children

The purpose of this clinical report is to discuss several recent advances in assessing exocrine pancreatic insufficiency (EPI) and pancreatitis in children, to review the array of pancreatic function tests, to provide an update on the inherited causes of EPI, with special emphasis on newly available genetic testing, and to review newer methods for evaluating pancreatitis.

Frequency of abnormal fecal biomarkers in irritable bowel syndrome

PRIMARY STUDY OBJECTIVE

Determine the frequency of abnormal fecal biomarker test results in patients with 13 irritable bowel syndrome (IBS)-related ICD-9 (International Statistical Classification of Diseases and Related Health Problems) codes.

STUDY DESIGN

Quantitative review of de-identified records from patients in whom IBS was a possible diagnosis.

METHODS

Records were selected for analysis if they included any of 13 IBS-related diagnostic codes and laboratory test results of fecal testing for all biomarkers of interest. Data collection was restricted to one 12-month period. Frequency distributions were calculated to identify rates of abnormal results for each biomarker within the total number of tests conducted in the eligible population.

RESULTS

Two thousand, two hundred fifty-six records were included in the study, of which 1867 (82.8%) included at least one abnormal value. Quantitative stool culture for beneficial bacteria (Lactobacillus and Bifidobacterium) indicated low growth suggestive of intestinal dysbiosis in 73.1% of records, followed by abnormally elevated eosinophil protein X (suggestive of food allergy) in 14.3%, elevated calprotectin (suggestive of inflammation) in 12.1%, detection of parasites in 7.5%, and low pancreatic elastase (suggestive of exocrine pancreatic insufficiency) in 7.1%.

CONCLUSIONS

Abnormal fecal biomarkers are prevalent in patients with diagnoses suggestive of IBS. Abnormal fecal biomarker testing, if confirmed in additional independent clinical trials, could substantially reduce the economic costs associated with diagnosis and management of IBS.

Novel Testing Enhances Irritable Bowel Syndrome Medical Management: The IMMINENT Study

Primary Study Objective:

To evaluate the economic utility of a fecal biomarker panel structured to suggest alternative, treatable diagnoses in patients with symptoms of irritable bowel syndrome (IBS) by quantifying, comparing, and contrasting health service costs between tested and non-tested patients.

Study Design:

Retrospective, matched cohort study comparing direct medical costs for IBS patients undergoing fecal biomarker testing with those of matched control subjects.

Methods:

We examined de-identified medical and pharmacy claims of a large American pharmacy benefit manager to identify plan members who underwent panel testing, were eligible for covered benefits for at least 180 days prior to the test date, and had data available for 30, 90, and 365 days after that date. We used propensity score matching to develop population-based control cohorts for each tested cohort, comprised of records with IBS-related diagnoses but for which panel testing was not performed. Primary outcome measures were diagnostic and medical services costs as determined from claims data.

Results:

Two hundred nine records from tested subjects met inclusion criteria. The only significant baseline differences between groups were laboratory costs, which were significantly higher in each tested cohort. At each follow-up time point, total medical and gastrointestinal procedural costs were significantly higher in non-tested cohorts. Within tested cohorts, costs declined significantly from baseline, while costs rose significantly in non-tested control cohorts; these differences were also significant between groups at each time point.

Conclusions:

Structured fecal biomarker panel testing was associated with significantly lower medical and gastrointestinal procedural costs in this study of patients with IBS symptoms.

Evolution of pancreatic function during the first year in infants with cystic fibrosis

OBJECTIVE

To describe pancreatic function during the first year of life in infants diagnosed with cystic fibrosis (CF) using serial fecal elastase measurements.

STUDY DESIGN

This was a longitudinal study of 82 infants diagnosed with CF through newborn screening. Monthly stool samples were sent to a central laboratory for fecal elastase measurements.

RESULTS

A total of 61 infants had an initial stool sample obtained at age <3.5 months and a final stool sample obtained at age >9 months. Twenty-six of 29 infants with a fecal elastase value <50 μg/g at study entry had a fecal elastase value <200 μg/g (the accepted cutoff value for pancreatic insufficiency) on all measurements during the year; all 29 had a value <200 μg/g at the end of the study. Of the 48 infants with initial fecal elastase value <200 μg/g, 13 had at least 1 fecal elastase value >200 μg/g but had a final stool fecal elastase value <200 μg/g; however, 4 infants with an initial fecal elastase value <200 μg/g ended the year with a value >200 μg/g. Eleven of 13 infants with an initial fecal elastase value of >200 μg/g still had a value >200 μg/g at the end of the first year.

CONCLUSION

Infants with CF exhibit variability in fecal elastase values during the first year. Infants with a fecal elastase level of 50-200 μg/g at diagnosis should be treated with pancreatic enzyme replacement therapy, but fecal elastase should be remeasured at age 1 year to ensure that those with a falsely low value do not continue to receive pancreatic enzyme replacement therapy unnecessarily. Those with a fecal elastase value >200 μg/g initially can become pancreatic insufficient with time.

Comparison of diagnostic methods for pancreatic insufficiency in infants with cystic fibrosis

OBJECTIVE

The objective of the present study is to compare daily weight gain and laboratory analysis (72-hour fecal fat and steatocrit) with fecal elastase-1 (EL-1) when diagnosing pancreatic insufficiency (PI) in infants with cystic fibrosis (CF).

METHODS

A total of 39 infants with CF, diagnosed consecutively by newborn screening at 2 referral centers, were included in the study. Daily weight gain and results of laboratory analysis of stool samples were compared using the κ coefficient and the receiver operator characteristic (ROC) curve.

RESULTS

Using the criterion of low daily weight gain, the frequency of PI was 92.3%; using the 72-hour fecal fat, steatocrit, and fecal EL-1 tests, the frequency was 42.3%, 86.2%, and 84.6%, respectively. EL-1 was used as the reference test. It was observed that the criteria of low daily weight gain (<50th percentile) and abnormal steatocrit, used together, showed the highest sensitivity (91.3%) and specificity (83.3%) for the diagnosis of PI.

CONCLUSIONS

When fecal EL-1 analysis is not immediately available, low daily weight gain associated with abnormal steatocrit can be adopted as a criterion for initiating pancreatic enzyme replacement therapy in infants with CF; however, EL-1 testing should be performed later for confirmation of PI.

Comparison of fecal elastase-1 and pancreatic function testing in children

OBJECTIVES

The fecal pancreatic elastase-1 (FE-1) test is considered a simple, noninvasive, indirect measure of pancreatic function. We aimed to evaluate the performance of the FE-1 test compared with the direct pancreatic function test (PFT) with secretin stimulation in children.

METHODS

Data of 70 children (6 months-17 years of age) who had both FE-1 test and PFT were analyzed.

RESULTS

The average FE-1 concentration was 403 ± 142 μg/g. Eleven children had concentrations below 200  μg/g, 23 between 201 to 500 μg/g, and 36 were above 500 μg/g. The average pancreatic elastase activity measured on direct stimulation was 49.1 ± 38.6  μmol · min (-1)· ml(-1) and 11 children had activity below the established cutoff (10.5 μmol · min(-1) · ml(-1)). Among the 11 children with pathologic PFT, 7 had normal FE-1, 4 were in the intermediate range (201-500 μg/g), and none were in the low range (<200 μg/g). Among the 59 children with normal direct PFT 11 (19%) had pathologic (<200 μg/g) and 19 (32%) had intermediate FE-1 tests. Twenty-nine children had both normal FE-1 concentration and normal PFT, giving a negative predictive value of 80%. The correlation between pancreatic elastase activity and FE-1 concentration was poor (r = 0.190). The sensitivity of the FE-1 test was found to be 41.7%, whereas the specificity was 49.2%. The positive predictive value of the FE-1 test was only 14%.

CONCLUSIONS

The FE-1 test is a simple, noninvasive, indirect method; however, ordering physicians should be aware of its limitations. It can give false-positive results and has low sensitivity in children with mild pancreatic insufficiency without cystic fibrosis and in those with isolated pancreatic enzyme deficiencies.

Quantitative MRCP assessment of pancreatic exocrine reserve and its correlation with faecal elastase-1 in patients with chronic pancreatitis

PURPOSE

This retrospective study was done to correlate a quantitative assessment of the pancreatic exocrine reserve by dynamic secretin magnetic resonance cholangiopancreatography (MRCPQ) with the faecal elastase-1 (FE-1) test in patients with chronic pancreatitis.

MATERIALS AND METHODS

Thirty-five patients with a clinical diagnosis of chronic (CP) or acute recurrent (ARP) pancreatitis were enrolled. FE-1 was indicative of the pancreatic exocrine reserve. Subsequently, the patient population was subdivided into two groups according to a clinical threshold value of 200 μg/g. All patients underwent MRCP examination during secretin administration. Duodenal filling volume was calculated on T2-weigthed rapid acquisition with relaxation enhancement (RARE) MRCP images obtained 10 min after secretin injection. Duodenal filling volumes were compared with FE-1 values. Scatter plots, Pearson correlation coefficient and the Mann-Whitney U test were performed.

RESULTS

Thirty-five paired MRCPQ-FE1 data sets were analysed. MRCPQ was significantly different (p=0.007) between patients with impaired and preserved pancreatic function; median and interquartile range (IQR) were 150.7 ml (137.3-205.5 ml; n=9) and 332.4 ml (190.6-506.9 ml; n=26). Both Pearson correlation coefficient (p<0.001) and the Mann-Whitney U test (p=0.007) were significant.

CONCLUSIONS

MRCPQ significantly correlates with FE-1 values. It is possible to discriminate impaired and preserved pancreatic exocrine function using MRCPQ.

Fecal pancreatic elastase-1 levels in older individuals without known gastrointestinal diseases or diabetes mellitus

Background

Structural changes occur in the pancreas as a part of the natural aging process. With aging, also the incidence of maldigestive symptoms and malnutrition increases, raising the possibility that these might be caused at least in part by inadequate pancreatic enzyme secretion due to degenerative processes and damage of the gland. Fecal elastase-1 is a good marker of pancreatic exocrine secretion. The aim of this study was to investigate the fecal elastase-1 levels among over 60 years old Finnish and Polish healthy individuals without any special diet, known gastrointestinal disease, surgery or diabetes mellitus.

Methods

A total of 159 patients participated in this cross-sectional study. 106 older individuals (aged 60-92 years) were recruited from outpatient clinics and elderly homes. They were divided to three age groups: 60-69 years old (n = 31); 70-79 years old (n = 38) and over 80 years old (n = 37). 53 young subjects (20-28 years old) were investigated as controls. Inclusion criteria were age over 60 years, normal status and competence. Exclusion criteria were any special diet, diabetes mellitus, any known gastrointestinal disease or prior gastrointestinal surgery. Fecal elastase-1 concentration was measured from stool samples with an ELISA that uses two monoclonal antibodies against different epitopes of human elastase-1.

Results

Fecal elastase-1 concentrations correlated negatively with age (Pearson r = -0,3531, P < 0.001) and were significantly lower among subjects over 70 years old compared to controls (controls vs. 70-79 years old and controls vs. over 80 years old, both P < 0.001). Among the over 60 years old subjects, the fecal elastase-1 concentrations were below the cut off level of 200 μg/g in 23 of 106 (21.7%) individuals [mean 112 (86-138) μg/g] indicating pancreatic exocrine insufficiency. Of those, 9 subjects had fecal elastase-1 level below 100 μg/g as a marker of severe pancreatic insufficiency.

Conclusion

In our study one fifth of healthy older individuals without any gastrointestinal disorder, surgery or diabetes mellitus suffer from pancreatic exocrine insufficiency and might benefit from enzyme supplementation therapy.

Exocrine and endocrine pancreatic function in 21 patients suffering from autoimmune pancreatitis before and after steroid treatment

BACKGROUND/AIM

Autoimmune pancreatitis (AIP) responds rapidly and dramatically to steroid therapy. The aim of this study was to evaluate pancreatic exocrine and endocrine function in patients suffering from AIP both before and after steroid therapy.

PATIENTS AND METHODS

Fecal elastase 1 and diabetes were evaluated before steroid therapy and within 1 month of its suspension in 21 patients (13 males and 8 females, mean age 43 +/- 16.5 years) diagnosed as having AIP between 2006 and 2008.

RESULTS

At clinical onset, fecal elastase 1 was 107 +/- 126 microg/g stool. Thirteen patients (62%) showed severe pancreatic insufficiency (<100 microg/g stool), 4 (19%) had mild insufficiency (100-200 microg/g stool), while 4 (19%) had normal pancreatic function (>200 microg/g stool). Before steroids, diabetes was diagnosed in 5 patients (24%), all of whom had very low levels of fecal elastase 1 (<19 microg/g stool). Following steroids, fecal elastase 1 increased in all patients (237 +/- 193 microg/g stool) and observed levels were significantly higher than those seen before steroids (p = 0.001).

CONCLUSIONS

Patients suffering from AIP display exocrine and/or endocrine pancreatic insufficiency at clinical onset. These insufficiencies improve after steroid therapy.

Tests of pancreatic exocrine function - clinical significance in pancreatic and non-pancreatic disorders

The pancreas functions as the main factory for digestive enzymes and therefore enables food utilisation. Pancreatic exocrine insufficiency, partial or complete loss of digestive enzyme synthesis, occurs primarily in disorders directly affecting pancreatic tissue integrity. However, other disorders of the gastrointestinal tract, such as coeliac disease, inflammatory bowel disease, Zollinger-Ellison syndrome or gastric resection can either mimic or cause pancreatic exocrine insufficiency. The overt clinical symptoms of pancreatic exocrine insufficiency are steatorrhoea and maldigestion, which frequently become apparent in advanced stages. Several direct and indirect function tests are available for assessment of pancreatic function but until today diagnosis of excretory insufficiency is difficult as in mild impairment clinically available function tests show limitations of diagnostic accuracy. This review focuses on diagnosis of pancreatic exocrine insufficiency in pancreatic and non-pancreatic disorders.

Exocrine pancreatic function testing in patients with cystic fibrosis and pancreatic sufficiency: a correlation study

OBJECTIVES

Most patients with cystic fibrosis (CF) have pancreatic insufficiency; however, 15% of the patients are pancreatic sufficient (PS). Several laboratory tests have been developed to distinguish between pancreatic insufficiency and PS. The gold standard to determine pancreatic function apart from direct pancreatic stimulation test is the 72-hour fecal fat excretion, expressed as coefficient of fat absorption (CFA). The aim was to test the correlation between 2 other tests, fecal elastase-1 and serum immunoreactive trypsinogen (IRT), as compared with fecal fat excretion.

PATIENTS AND METHODS

21 patients with CF-PS performed the 3 tests of fecal fat excretion, fecal elastase-1, and IRT. Correlation between the tests was evaluated by the kappa statistics test, sensitivity and specificity, and positive and negative predictive values.

RESULTS

CFA was abnormal in 5 patients, elastase was <200microg/g in 4 patients, and IRT was <20 ng/mL in 2 patients. The correlation between CFA and IRT was negative(kappa=-0.154), and between CFA and fecal elastase-1 was poor (kappa=0.213). The sensitivity, specificity, and positive and negative predictive values of IRT versus CFA were 0%, 88%, 0%, and 78%, and for fecal elastase-1 were 40%, 81%, 40%, and 81%, respectively.

CONCLUSIONS

In CF-PS, poor correlation was found between IRT, fecal elastase-1, and CFA, therefore neither fecal elastase-1 in the stool nor IRT in the serum reaches the sensitivity or the specificity of the fecal fat excretion. Thus, fecal fat excretion is required in patients with CF for evaluation of pancreatic function.

Development and validation of an improved test for the measurement of human faecal elastase-1

BACKGROUND

Human faecal elastase-1 (FE-1) is an established biochemical test for the investigation of pancreatic exocrine insufficiency. Conventional extraction methods for FE-1 analysis can give false-positive results with watery stools. This is a major limitation as patients investigated for pancreatic disease commonly produce such stools. We have developed an improved FE-1 test that overcomes water interference by measuring the enzyme in dried faeces.

METHODS

A novel collection device for FE-1 analysis that involves drying and weighing the stool sample was developed in our laboratory and compared with a conventional wet method, E1 Quick-Prep (Schebo, Biotech AG, Germany). The concentration of faecal FE-1 was determined using a commercially available enzyme-linked immunosorbent assay method (Schebo).

RESULTS

FE-1 values obtained using the new dry extraction procedure (mean 1777 microg/g dry stool) were higher when compared with the conventional wet analysis (mean 402 microg/g stool). A 1:2 dilution in water, mimicking a loose stool, was found to affect FE-1 results obtained using the conventional wet extraction procedure. The new dry extraction method gave consistent results when water content was varied in the original stool sample.

CONCLUSION

We have demonstrated that our new device overcomes water interference, allowing results to be obtained from stool samples that would otherwise be unsuitable for FE-1 analysis.

The changing face of the exocrine pancreas in cystic fibrosis: pancreatic sufficiency, pancreatitis and genotype

(Table is included in full-text article.)Cystic fibrosis (CF) is the most frequent cause of exocrine pancreatic insufficiency in childhood. The cystic fibrosis transmembrane conductance regulator (CFTR) gene encodes CFTR protein that functions as cyclic AMP-dependent chloride channel allowing the passage of anions and secondarily water into the lumen of pancreatic ducts. Luminal chlorides are exchanged for bicarbonates. The lack of CFTR channel or its disrupted function (being the consequence of CFTR gene mutations) results in reduced volume of more acidic secretion. It has been suggested that such a situation leads to the precipitation of highly concentrated protein-containing secretion with obstruction and organ damage. The intensity of this process determines the progression of the disease. Steatorrhea is the significant symptom of classical form of CF. Residual pancreatic secretion in a subset of patients, however, allows for normal lipid digestion and absorption. Previous cross-sectional clinical studies estimated that about 85-90% of CF patients in preschool, school and older age are pancreatic insufficient. More frequent detection of mild and nonclassic forms of CF leads to higher frequency of pancreatic sufficiency (PS). The potential decline of exocrine pancreatic function, however, should be always considered. All PS patients with at least one severe or unknown CFTR mutation should be longitudinally assessed for the progression of pancreatic dysfunction. Recurrent acute and chronic pancreatitis is not a rare clinical condition in PS patients with PS: it might be the presenting symptom, even preceding CF diagnosis by several years. Potential appearance of this complication in individuals with pancreatic insufficiency demands elucidation.

The elimination of meat from the diet selectively decreases pancreatic elastase secretion

Since the vegetarian diet lacks the substrate for pancreatic elastase-1 as an enzyme, a decreased secretion of this enzyme could be expected. We aimed therefore to assess the changes of exocrine pancreatic secretion in a prospective way in a group of healthy omnivores who modified their diet by abstaining from meat for 1 month. Twenty healthy omnivores (fourteen females and six males) were used in the study. The nutrient intake was assessed for 7 d before commencing the study (omnivore diet) and after 1 month of dietary modification (modified diet; meat excluded). Similarly, the faecal output of pancreatic enzymes (elastase-1, chymotrypsin and lipase) was assessed before and 1 month after the period of dietary modification. Statistical differences between two points of the assessment (paired data) were calculated with the use of the Wilcoxon rank test. The relationship between the changes of faecal enzyme output and the changes in nutrient intake was assessed using multiple regression analysis. The dietary changes resulted in statistically significant decrease of faecal elastase-1 output (P < 0·05), whereas for chymotrypsin and lipase no changes were observed. No significant change in stool weight was recorded. No statistically significant correlation between changes in energy and nutrient consumption and changes in faecal output of pancreatic enzymes has been found. It was concluded that the exclusion of meat from the diet for a 1-month period results in significant changes in pancreatic secretion with a selective decrease of elastase-1 output. However, the underlying factor remains unclear.

Fecal elastase-1: utility in pancreatic function in cystic fibrosis

Early detection and management of pancreatic insufficiency is essential to optimize health and outcomes in cystic fibrosis patients. The gold standard measures for assessment of pancreatic function are direct pancreatic stimulation tests, which have numerous limitations. Estimation of fecal elastase-1 level to determine pancreatic function is an attractive alternative as the test is simple, rapid, cost-effective and easy to perform even in children. This review summarizes the data from studies reflecting the validity, limitation and advantages of fecal elastase-1 in assessing pancreatic function in cystic fibrosis patients.

Towards the ideal quantitative pancreatic function test: analysis of test variables that influence validity

BACKGROUND & AIMS

Although pancreatic stimulation tests quantify acinar and ductal exocrine pancreatic function, no standard methodology exists. We evaluated the impact of several variables on test accuracy.

METHODS

We performed a retrospective analysis of pancreatic stimulation tests, which involved continuous stimulation with cholecystokinin and secretin, 3 sampling periods (20-min each), and perfusion markers to correct for intestinal losses. Results were recalculated using the following variables: no correction for losses; shortened sampling time (20-min); no correction and shortened sampling time; and enzyme concentration. We examined how these variables influenced measurements of pancreatic secretion and classification of pancreatic function status (sufficient or insufficient).

RESULTS

We analyzed 363 tests in control patients (20), and patients with cystic fibrosis (137), Shwachman-Diamond syndrome (40), or other pancreatic or intestinal disorders (166). Recovery of pancreatic juice varied markedly between tests (median, 59%; range, 4%-106%) and was significantly poorer during the first 20-minute period compared with the 2 subsequent periods (P < .01). Failure to correct for intestinal losses underestimated secretory capacity (median trypsin output reduced by >50%, P < .0001) and shortened sampling time increased test variability. Both variables together resulted in greater discrepancies. More than 25% of the pancreatic-sufficient patients with impaired pancreatic function were misclassified as pancreatic insufficient when uncorrected output plus a shortened sampling time or enzyme concentration were used to define categories.

CONCLUSIONS

Pancreatic function tests using brief aspiration periods without marker perfusion or measures of concentration greatly underestimate pancreatic secretory capacity and misclassify the clinical status of an unacceptably large number of patients.

Fecal elastase: pancreatic status verification and influence on nutritional status in children with cystic fibrosis

OBJECTIVES

To evaluate fecal elastase 1 (FE) levels in young children with cystic fibrosis and pancreatic insufficiency and to explore the relationship between FE and growth, nutrition, pulmonary status and fat absorption over a 24-month period.

METHODS

FE, indicating pancreatic lipase activity, was assessed in children (6.0 to 8.9 years of age) with cystic fibrosis and pancreatic insufficiency. FE >15 microg/g stool was defined as residual pancreatic activity, suggesting some pancreatic function, and FE </=15 microg/g stool was defined as no pancreatic activity, suggesting pancreatic insufficiency. Seven-day weighed food records were collected and coefficient of fat absorption was calculated using dietary records and 72-hour stool collection. Height adjusted for mid-parental height, weight, body mass index, upper arm muscle area and upper arm fat area were measured and Z scores were calculated. Forced expiratory volume in 1 second was the measure of pulmonary function.

RESULTS

Ten children (12%) had residual pancreatic activity (range, 17 to 667 microg/g stool) and 75 had no pancreatic activity. Children with no pancreatic activity had significantly lower coefficients of fat absorption than did those with residual pancreatic activity (81% +/- 14% versus 94% +/- 3%; P = 0.009) and significantly lower adjusted height Z score (-0.8 +/- 1.0 versus -0.1 +/- 1.3; P = 0.03). Children with residual pancreatic activity had significantly greater improvement in weight for age Z scores, upper arm muscle area Z scores, and upper arm fat area Z scores than children with no pancreatic activity (P </= 0.01). Children with no pancreatic activity were significantly (P = 0.007) more likely to have the DeltaF508/DeltaF508 genotype than were those with residual pancreatic activity (61% versus 11%).

CONCLUSIONS

These data suggest that a substantial number (12% in this sample) of children with cystic fibrosis have a misclassified pancreatic status. Children with residual FE had greater fat absorption and improved growth and nutritional status over 24 months. FE assessment should be used to verify pancreatic status in patients with cystic fibrosis.

Early decline of pancreatic function in cystic fibrosis patients with class 1 or 2 CFTR mutations

BACKGROUND

Most cystic fibrosis (CF) patients develop steatorrhea and require pancreatic enzyme replacement therapy. However, there are few data regarding the decline of exocrine pancreatic function within the first years of life in relation to CF genotype. We assessed the decline of pancreatic function in CF infants carrying class 1 or 2 CFTR mutations who were diagnosed in a neonatal screening program.

MATERIALS AND METHODS

Twenty-eight CF patients were included in the study and 27 completed the study. In all subjects, fecal pancreatic elastase-1 concentrations and fecal fat excretion were scheduled to be determined at diagnosis, at 6 months of age and subsequently at 6-month intervals.

RESULTS

In all CF patients, fecal pancreatic elastase-1 concentrations of the first assay after diagnosis (3 to 4 months of age) were lower than the cut-off level for normals of <200 microg/g stool. Steatorrhea was found in 81.5% of these subjects. At the age of 6 months, all screened CF subjects had fecal pancreatic elastase-1 concentrations <100 microg/g and at the age of 12 months all were pancreatic insufficient. At that time, having proved pancreatic insufficiency in all studied subjects, we stopped the scheduled further assessment.

CONCLUSION

CF patients require careful monitoring of pancreatic status from diagnosis onwards. In patients carrying class 1 or 2 CFTR mutations, pancreatic insufficiency develops in the first months of life. The proper assessment of pancreatic insufficiency and intestinal malabsorption is crucial for the early introduction of pancreatic enzymes.

Faecal elastase-1 test is superior to faecal lipase test in the assessment of exocrine pancreatic function in cystic fibrosis

BACKGROUND AND AIMS

Direct tests are characterized by the highest sensitivity and specificity. However, their practical use, especially in children, is limited. Among the indirect tests, the highest sensitivity and specificity was documented for faecal elastase-1 test, yet the value of faecal lipase test in cystic fibrosis (CF) has not been defined. Therefore, the aim of the present study was to compare the sensitivity and the specificity of the faecal lipase test to the faecal elastase-1 test in the assessment of exocrine pancreatic function in children with CF.

METHODS

The study comprised 90 CF patients and 95 healthy subjects (HS). In all subjects, faecal elastase-1 concentrations (ELISA) and lipase activities (ELISA) were measured. The presence of pancreatic insufficiency was documented by the determination of faecal fat excretion in 78 pancreatic insufficient and by the secretin-cholecystokinin test in 12 CF patients without steatorrhoea. Sensitivity and specificity of the faecal elastase-1 test and faecal lipase test were analysed and, in 50 HS, sample-to-sample and day-to-day variations were determined.

RESULTS

With cut-off levels providing the same specificity for both tests (95.8%), the sensitivity of the faecal elastase-1 test (91.1%) was significantly higher (p < 0.0036) than that of the faecal lipase test (76.7%). Sample-to-sample (mean +/- SEM: 13.2 +/- 1.2% vs 23.4 +/- 2.2%) and day-to-day variations (mean +/- SEM: 16.3 +/- 1.2% vs 32.5 +/- 2.6%) were significantly lower (p < 0.0001) for elastase-1 than for lipase measurements.

CONCLUSION

Among indirect tests, faecal elastase-1 test is superior to faecal lipase test in the assessment of exocrine pancreatic function in cystic fibrosis.

Now that fecal elastase is available in the United States, should clinicians start using it?

Fecal elastase-1 estimation is an alternative fecal enzyme test for the detection of exocrine pancreatic insufficiency, which, in contrast to chymotrypsin estimation, uses monoclonal antibodies against human pancreatic elastase and is thus unaffected by simultaneous pancreatic enzyme replacement therapy. Similar to other indirect pancreatic function tests, it has a high sensitivity rate for detecting severe functional impairment of the gland. However, the two major problems for the clinician--namely diagnosing mild to moderate exocrine pancreatic insufficiency or chronic pancreatitis and differentiating pancreatic from nonpancreatic steatorrhea or diarrhea--cannot be solved by pancreatic elastase-1 determination. The test cannot be used in non-formed stool (ie, diarrhea) unless the stool is lyophilized. All in all, this new test does not seem to be the gold standard for pancreatic function that we have been waiting for.

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.

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.

Low fecal elastase: potentially related to transient small bowel damage resulting from enteric pathogens

Fecal elastase is considered to be a highly sensitive and specific non-invasive exocrine pancreatic function test. However, enteropathy may theoretically cause decreased exocrine pancreatic enzyme secretion through alteration of enteric hormone release.

OBJECTIVE

The aim of this study was to evaluate the possible influence of transient small bowel damage on pancreatic elastase secretion.

METHODS

We studied 166 children (aged 4 months to 14 years, mean 2 years); 114 of these children had acute enteritis and 52 children were control subjects (with gastro-intestinal symptoms or extra-intestinal diseases). Feces were collected from each patient 3 days after the onset of diarrhea and then tested for fecal elastase, bacterial pathogens, Rotavirus, and Adenovirus. Liquid fecal samples were not considered eligible for elastase measurement. Pancreatic elastase was measured using an ELISA method (Sche.Bo.Tech, Germany). We classified the results, expressed in microg/g stool, as: severe pancreatic insufficiency (<100 microg/g), moderate pancreatic insufficiency (100 to 200 microg/g), and normal (>200 microg/g).

RESULTS

In the acute enteritis group we found severe levels in 14 (12%) children, moderate levels in 18 children (16%), and normal levels in 82 children (72%). In contrast, 52 of 52 (100%) control subjects demonstrated normal results. Statistical analysis (Wilcoxon rank test) demonstrated a significant difference between the enteritis and control groups (P < 0.01). Serial measurement of fecal elastase performed in 10 patients with enteritis showed a progressive increase of levels in 6 patients and an early decline with subsequent increases in the other 4 patients.

CONCLUSIONS

Transient exocrine pancreatic insufficiency may be present in transient small bowel disease, caused by both bacterial and viral infections, possibly related to reduced enteric CCK secretion.

Inhibition of endogenous pancreatic enzyme secretion by oral pancreatic enzyme treatment

BACKGROUND

The existence of a feedback mechanism for exocrine pancreatic secretion in humans is controversial. Exclusion of proteases from the duodenum stimulates exocrine pancreatic secretion. Conversely, addition of exogenous enzymes could reduce the enzyme secretion. Further investigation of the feedback mechanism should be performed under the most physiological conditions. In the present study we investigated exocrine pancreatic function by measuring fecal enzyme output in healthy volunteers consuming a normal diet, before and during a time course of exogenous pancreatic enzyme supplementation.

MATERIAL AND METHODS

Twenty-five healthy subjects (HS) were given two different doses (30 and 60 FIP proteases kg(-1) d(-1)) divided by the number of meals. In all subjects, fecal elastase-1 (E1) concentrations and chymotrypsin (ChT) activities were measured without and with enzyme supplements after 7 days of treatment. In eight subjects, E1 concentrations and ChT activities were measured daily for 10 consecutive days. The subjects were given a dose regimen of 100 FIP proteases kg(-1) d(-1)(divided by the number of meals) for the first 7 days.

RESULTS

Oral pancreatic treatment dose-dependently inhibited endogenous pancreatic secretion measured with the use of E1 concentrations. In both regimen groups, the differences were statistically significant. The exogenous enzymes, which interfere with colorimetric method for ChT, dose-dependently increased ChT output. However, only the higher dose resulted in a statistically significant difference. In the subgroup of eight HS, time-dependent changes of fecal enzyme output occurred with a decrease of E1 concentrations and an increase of ChT activity from the second up to eighth or ninth day of the experiment.

CONCLUSION

Exogenous applied pancreatic enzymes, dose- and time-dependently inhibited endogenous pancreatic secretion. The obtained results strongly support the existence of a protease mediated feedback mechanism in humans.

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.

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 determination in the diagnosis of chronic pancreatitis]

The diagnosis of chronic pancreatitis is based on morphological and functional data. To evaluate exocrine function, the secretin-cholecystokinin test is the gold standard but this is invasive and frequently unavailable. Recently, fecal elastase-1 determination has been investigated as an indirect test of pancreatic function.

OBJECTIVE

To evaluate the diagnostic value of fecal elastase-1 in chronic pancreatitis by comparing it with other indirect methods of evaluating pancreatic function such as the urine pancreolauryl test and fecal chymotrypsin determination. To do this, we analyzed the three diagnostic methods in four groups of patients: group I (14 patients with confirmed chronic pancreatitis); group II (5 patients with recurrent episodes of acute alcoholic pancreatitis; group III (9 patients with non-pancreatic diarrhea); group IV (8 patients with other gastrointestinal diseases).

RESULTS

Compared with the control groups (groups III and IV), patients in groups I and II presented lower levels of fecal elastase-1 (groups I-II: 88 mcg/g, groups III-IV: 635 mcg/g, p < 0.0001), fecal chymotrypsin (4.3 U/g and 29.3 U/g, respectively, p < 0.0001), and pancreolauryl (14% and 54%, respectively, p < 0,001). In the diagnosis of confirmed chronic pancreatitis (group I) the fecal elastase-1 and pancreolauryl tests showed a sensitivity of 85.6% and 78.5%, respectively. However, in group II, the most sensitive test was the pancreolauryl test (80% versus 60% for the chymotrypsin test and only 40% for the fecal elastase-1 test). In contrast, the fecal elastase-1 test showed the highest specificity (94.1% versus 88.2% for the fecal chymotrypsin test and 81.3% for the pancreolauryl test).

CONCLUSION

Fecal elastase-1 determination is an effective indirect method in the diagnosis of patients with advanced chronic pancreatitis. However, when the disease is in the early stages, its sensitivity is no greater than that of other indirect tests. The greatest advantage of this test is its high specificity.

Fecal elastase-1 as a test for pancreatic function: a review

Pancreatic elastase-1 is a specific human protease synthetized by the acinar cells. Immunoreactive elastase-1 cannot be detected in either porcine or bovine pancreatic enzyme preparations. It is very stable and, in contrast to fecal chymotrypsin, elastase is unaffected by exogenous pancreatic enzyme treatment, and correlates well with exocrine pancreatic function tests. The measurement of this proteolytic enzyme in stool by means of an enzyme-linked immunosorbent assay (ELISA) is a sensitive, specific, and relatively inexpensive non-invasive test. It is an accurate function test for patients with chronic pancreatitis confirmed by endoscopic retrograde cholangiopancreatography and computerized axial tomography. It shows higher sensitivity and specificity for exocrine pancreatic insufficiency than fecal chymotrypsin determination and is comparable to oral pancreatic function tests such as the pancreolauryl test.