Interpretations: How to use faecal elastase testing

Preanalytical and analytical factors affecting elastase quantitation in stool

Exocrine pancreatic insufficiency (EPI) is a condition caused by a deficiency of exocrine pancreatic enzymes, resulting in malabsorption of nutrients. Clinical manifestations of EPI may include steatorrhea, weight loss, diarrhea, and abdominal pain. Although direct testing is the most sensitive and specific for EPI, these tests are invasive, time consuming, expensive, and not well standardized. Fecal elastase (FE-1) has been shown to be an indirect marker of the exocrine secretory capacity of the pancreas and has become the most commonly employed indirect test for diagnosis of EPI. Measurement of fecal elastase consists of two main phases, a preanalytical phase and analytical phase. The preanalytical phase involves stool collection, storage and handling. The second phase is the analytical phase, which includes the actual assay processes and products used to produce a result. For FE-1 this includes sample extraction and measurement on an immunoassay. Each step in the process can influence the result and contribute to heterogeneity in FE-1 measurement, potentially impacting clinical diagnosis and management. Thus, this paper provides an overview of the preanalytical and analytical factors that can affect measurement and interpretation of FE-1 results.

Stool Elastase as an Independent Prognostic Factor in Patients with Pancreatic Head Cancer

(1) Background: Patients with pancreatic exocrine insufficiency (PEI) have an increased risk of malnutrition, which in turn increases morbidity and mortality and is frequent in pancreatic head cancer. This study aimed to analyze the utility of PEI measured using the stool elastase (SE) level to predict the prognosis of patients with pancreatic head cancer. (2) Methods: Patients who underwent pancreaticoduodenectomy for pancreatic cancer at our institution between 2011 and 2015 were included. Only patients with data on preoperative SE levels were analyzed. Patients were classified into low and high SE groups based on preoperative SE levels (low < 100 µg/g < high). (3) Results: The median preoperative SE level was 67.2 µg/g, and 84 of 143 (58.7%) patients were included in the low SE group. The two groups had significantly different overall survival (OS) and disease-free survival (DFS), and the low SE group had a worse prognosis. In multivariate analysis, SE level < 100 µg/g and lymph node metastasis were independent poor prognostic factors for OS and DFS. (4) Discussion: PEI measured using SE levels is an independent prognostic factor in patients with pancreatic head cancer undergoing pancreaticoduodenectomy. Since poor nutritional status may be related to prognosis in patients with low levels of stool elastase preoperatively, aggressive treatment may be required.

Assessment of Exocrine Function of Pancreas Following Pancreaticoduodenectomy

Pancreatic exocrine insufficiency (PEI) is a common long-term complication after pancreaticoduodenectomy (PD) and is observed in 23-80% of patients. As the postoperative mortality after PD has substantially decreased, it warrants more attention on the diagnosis and treatment of functional long-term consequences after PD. These include PEI and endocrine insufficiency that can result in significant nutritional impairment and often adversely impacts quality of life (QOL) of the patient. A PubMed search was performed for articles using key words "pancreatic exocrine insufficiency"; "pancreaticoduodenectomy"; "quality of life after pancreaticoduodenectomy"; "stool elastase"; "direct, indirect tests for pancreatic exocrine insufficiency"; "pancreatic enzyme replacement therapy." Relevant studies were shortlisted and analyzed. This review summarizes relevant studies addressing PEI following PD. We also discuss functional changes after PD, risk factors and predictive factors for postoperative PEI, clinical symptoms, direct and indirect tests for estimation of PEI, pancreatic enzyme replacement therapy (PERT), and QOL after pancreatic resection for malignancy. It was found that significant PEI occurs in most patients following PD. Fecal elastase 1 is an easy indirect test and should be performed routinely in both symptomatic and asymptomatic patients after PD. PERT should be considered in every patient after PD with the aim to improve the QOL and perhaps even their long time survival.

Fecal Elastase Levels Predict Honeycombing in Pancreas Detected with Endoscopic Ultrasound

BACKGROUND AND STUDY AIMS

We aimed to demonstrate the association between fecal elastase levels and Rosemont categories in patients with chronic changes in pancreas detected with endoscopic ultrasound.

PATIENTS AND METHODS

Patients were selected consecutively from endosonography examinations performed for upper gastrointestinal subepithelial lesions and for pancreas evaluation. Pancreas imaging findings were categorized according to the Rosemont criteria using echoendoscope. Patients who were indeterminate of, suggestive of, and consistent with chronic pancreatitis were included in the study. Fecal elastase measurements were performed after the patients were qualified to participate in the study according to endosonography findings.

RESULTS

Seventy patients were included in the study. 54 of them were male. Mean age of the patients was 51.7 ± 10.2 year. There were 36 patients in the indetermine group for chronic pancreatitis. Mean fecal elastase level was 507.1 ± 14.6 μg/g in the indeterminate group. There were 24 patients in the suggestive group of chronic pancreatitis. Mean fecal elastase level was 400.4 ± 121.4 μg/g in the suggestive group of chronic pancreatitis. There were 10 patients, in the consistent group with chronic pancreatitis. Mean fecal elastase level was 134.8 ± 86.1. The difference between the three groups of fecal elastase values was statistically significant compared with Kruskal Wallis test. Ordinal logistic regression analysis showed that there was a significant relation between endosonografic categories and fecal elastase values with Nagelkerke value of 0.704.

CONCLUSIONS

Fecal elastase levels of each of the endosonographic categories were significantly different from each other. Also, fecal elastase values can predict chronic changes in pancreas detected with endoscopic ultrasound.

Pancreatic Enzyme Replacement Therapy in Children with Severe Acute Malnutrition: A Randomized Controlled Trial

OBJECTIVE

To assess the benefits of pancreatic enzyme replacement therapy (PERT) in children with complicated severe acute malnutrition.

STUDY DESIGN

We conducted a randomized, controlled trial in 90 children aged 6-60 months with complicated severe acute malnutrition at the Queen Elizabeth Central Hospital in Malawi. All children received standard care; the intervention group also received PERT for 28 days.

RESULTS

Children treated with PERT for 28 days did not gain more weight than controls (13.7 ± 9.0% in controls vs 15.3 ± 11.3% in PERT; P = .56). Exocrine pancreatic insufficiency was present in 83.1% of patients on admission and fecal elastase-1 levels increased during hospitalization mostly seen in children with nonedematous severe acute malnutrition (P <.01). Although the study was not powered to detect differences in mortality, mortality was significantly lower in the intervention group treated with pancreatic enzymes (18.6% vs 37.8%; P < .05). Children who died had low fecal fatty acid split ratios at admission. Exocrine pancreatic insufficiency was not improved by PERT, but children receiving PERT were more likely to be discharged with every passing day (P = .02) compared with controls.

CONCLUSIONS

PERT does not improve weight gain in severely malnourished children but does increase the rate of hospital discharge. Mortality was lower in patients on PERT, a finding that needs to be investigated in a larger cohort with stratification for edematous and nonedematous malnutrition. Mortality in severe acute malnutrition is associated with markers of poor digestive function.

TRIAL REGISTRATION

ISRCTN.com: 57423639.

Pancreatic exocrine insufficiency: Comparing fecal elastase 1 with 72-h stool for fecal fat estimation

INTRODUCTION

Identification of pancreatic exocrine insufficiency (PEI) is important in the management of chronic pancreatitis. The 72-h stool for fecal fat estimation (FFE) has long been considered a gold standard indirect test for the diagnosis of PEI. However, the test is cumbersome for both patients and laboratory personnel alike. In this study, we aimed to assess fecal elastase 1 (FE1) as an alternate to FFE for the diagnosis of PEI.

METHODS

In all, 87 consecutive patients diagnosed with chronic pancreatitis were included in this study. FFE and FE1 estimation was done for all the patients. For FE1, two cutoffs (<100 and <200 μg) were selected to define pancreatic exocrine insufficiency. The sensitivity, specificity, and positive and negative predictive values for the two cutoffs were estimated. Kappa statistics was used to assess degree of agreement between both tests.

RESULTS

All patients completed the study and were included in the analysis. The sensitivity, specificity, and positive and negative predictive value and PABAK (prevalence and bias adjusted kappa) for FE1 <100 μg was 84.9, 47.6, 83.6, 50, and 0.52, respectively. For FE1 <200 μg, it was 90.9, 9.5, 75.95, 25, and 0.43, respectively.

CONCLUSION

FE1 is a sensitive test; however, it does not have a good agreement with FFE. FE1 may be used as screening test for PEI in patients with chronic pancreatitis.

Both Exocrine Pancreatic Insufficiency and Signs of Pancreatic Inflammation Are Prevalent in Children with Complicated Severe Acute Malnutrition: An Observational Study

OBJECTIVES

To assess whether pancreatic function is impaired in children with severe acute malnutrition, is different between edematous vs nonedematous malnutrition, and improves by nutritional rehabilitation.

STUDY DESIGN

We followed 89 children with severe acute malnutrition admitted to Queen Elizabeth Central Hospital in Blantyre, Malawi. Stool and blood samples were taken on admission and 3 days after initial stabilization to determine exocrine pancreatic function via fecal elastase-1 (FE-1) and serum trypsinogen and amylase levels.

RESULTS

A total of 33 children (37.1%) had nonedematous severe acute malnutrition, whereas 56 (62.9%) had edematous severe acute malnutrition. On admission, 92% of patients showed evidence of pancreatic insufficiency as measured by FE-1 <200 μg/g of stool. Patients with edematous severe acute malnutrition were more likely to have low FE-1 (98% vs 82.8%, P = .026). FE-1 levels remained low in these individuals throughout the assessment period. Serum trypsinogen was elevated (>57 ng/mL) in 28% and amylase in 21% (>110 U/L) of children, suggesting pancreatic inflammation.

CONCLUSION

Exocrine pancreatic insufficiency is prevalent in children with severe acute malnutrition and especially in children with edematous severe acute malnutrition. In addition, biochemical signs suggestive of pancreatitis are common in children with severe acute malnutrition. These results have implications for standard rehabilitation treatment of children with severe acute malnutrition who may benefit from pancreatic enzyme replacement therapy.

TRIAL REGISTRATION

ISRCTN.com: 13916953.

Comparison of fecal elastase 1 for exocrine pancreatic insufficiency evaluation between ex-alcoholics and chronic pancreatitis patients

CONTEXT

Fecal elastase is a noninvasive test for pancreatic insufficiency diagnosis.

OBJECTIVES

Evaluate the usefulness of fecal elastase 1 for the indication of exocrine pancreatic insufficiency among former alcohol addicts and patients with chronic pancreatitis.

METHODS

Forty-three patients with chronic pancreatitis and thirty-three asymptomatic former alcohol addicts entered the study. The levels of fecal elastase 1 were measured using a commercial kit. Pancreatic imaging findings were used to categorize the groups.

RESULTS

The levels of fecal elastase 1 were significantly lower in the patients than in the former alcohol addicts and in the group with tissue calcifications, duct alterations, or atrophy. With a cutoff level of 100 μg/g, the sensitivity of fecal elastase 1 in chronic pancreatitis was 46.51% and its specificity was 87.88% with a positive predictive value of 83.33% and a negative predictive value of 55.77%. When patients were stratified according to the severity of their pancreatitis, the sensitivity was 6.25% for mild pancreatitis and 70.37% for marked pancreatitis.

CONCLUSION

Low level of fecal elastase 1 was associated with marked rather than mild chronic pancreatitis; however, it may be useful to indicate pancreatic exocrine insufficiency in asymptomatic former alcohol addicts.

Quantification of pancreatic function using a clinically feasible short endoscopic secretin test

OBJECTIVES

Clinical and morphological criteria are not precise enough to diagnose early chronic pancreatitis (CP). We investigated if short endoscopic pancreas function testing as a part of routine upper endoscopy could improve clinical diagnostics.

METHODS

Patients with suspected CP underwent modified secretin-stimulated upper endoscopy (short endoscopic secretin test, or EST). Duodenal juice was collected during 15 minutes starting 30 minutes after stimulation. A modified scoring system for CP after Layer with bicarbonate and fecal elastase 1 (FE1) was used. We tested with receiver operating characteristic curves the diagnostic accuracy of bicarbonate and FE1 and with analysis of variance how precise the 2 parameters can discriminate the groups.

RESULTS

Fifty-two patients aged 19 to 67 years and 25 healthy controls aged 19 to 64 years were included. Twenty-four patients fulfilled the modified Layer Score for CP or non-CP. The overall accuracy of the EST versus FE1 test was 85%/71%, with positive and negative predictive values of 100%/79% and 80%/69%, respectively.

CONCLUSIONS

Short EST is rapid and easy to perform and can be incorporated in daily routines. We demonstrate that EST is superior to FE1 in the assessment of pancreatic insufficiency and may prove to be useful in diagnosing early or mild CP.

Fecal calprotectin and alpha-1 antitrypsin predict severity and response to corticosteroids in gastrointestinal graft-versus-host disease

Diagnosis of gastrointestinal GVHD (GI-GVHD) is based on clinical symptoms and histologic findings. No biomarkers predicting responses to treatment are routinely available even though 30% to 50% of patients will not respond to corticosteroids. In this study, we aimed to evaluate fecal calprotectin, α-1-antitrypsin (α(1)-AT), and elastase at the time of first symptoms as diagnostic and prognostic tools for GI-GVHD in 72 consecutive patients, of whom 51 developed GI-GVHD. The prognostic value of markers was evaluated by their association with complete response (CR) and steroid-resistant (SR) GVHD. Calprotectin and α(1)-AT concentrations increased with GI-GVHD initial stages but patients with initial stage 1 GI-GVHD had similar marker levels to patients without GI-GVHD, so sensitivity to diagnose GI-GVHD was weak. In contrast, calprotectin and α(1)-AT were predictors for SR-GVHD and CR. Multiple regression modeling identified calprotectin and α(1)-AT concentration as independently predicting SR-GVHD together with initial stage > 2 GI-GVHD. Our results showed that fecal calprotectin and α(1)-AT levels at the time of diagnosis are predictive for responses to treatment but are not diagnostic markers for initial stage 1 to 3 GI-GVHD.