Comparison of monoclonal and polyclonal ELISAs for fecal elastase in patients with cystic fibrosis and pancreatic insufficiency

Impact of acid blocker therapy on growth, gut microbiome, and lung disease in young children with cystic fibrosis

OBJECTIVE

Acid blocker therapy (ABT) has become common in cystic fibrosis (CF), despite insufficient evidence for benefits and studies showing potentially negative effects. We examined associations between ABT usage and growth, gut microbiome (GM), and early-onset lung disease in young children with CF.

METHODS

One hundred forty-five infants with CF born during 2012-2017, diagnosed through newborn screening by age 3 months and followed to 36 months of age at six CF centers were evaluated. Longitudinal data on growth, pancreatic functional status, pulmonary symptoms, and acid blocker medications were prospectively collected. Early-onset lung disease severity was evaluated by a clinical scoring system. GM composition was assessed by 16S rRNA methodology.

RESULTS

ABT use before age 3 years was frequent, with 81 (56%) of patients on H2 receptor antagonist (H2RA) or proton pump inhibitor (PPI), and higher among pancreatic insufficient (60%) versus pancreatic sufficient (26%) children. H2RA was commonly prescribed in infancy before transitioning to PPI. Growth improvements were not significantly greater, while GM α-diversity at 3 years of age was significantly lower and early-onset lung disease more severe, in persistent ABT users compared to nonusers of ABT.

CONCLUSION

In our cohort of young children with CF, early and persistent ABT use was not associated with significant growth benefits and instead showed associations with reduced GM diversity and negative effects on early-onset lung disease. Consequentially, there is a critical need for systematic evaluation and comprehensive risk-benefit analysis of ABT to ensure proper guidelines for children with CF.

Clinical and Analytical Comparison of Monoclonal and Polyclonal Immunoassays for Fecal Pancreatic Elastase

BACKGROUND

Numerous immunoassays have been commercialized to determine pancreatic elastase (PE) in feces in screening for exocrine pancreatic insufficiency (EPI), but how the different assays compare to one another is controversial, especially in the context that all methods use the same cut-off values for interpreting the results obtained on the presence or absence of EPI or the degree of insufficiency if it is present. Our aim was to analytically verify a new method for determining PE, compare the results with a previous method, and verify the declared cut-off values for interpretation of the results.

METHODS

PE in the stool was assayed using a previous monoclonal enzyme-linked immunosorbent assay ("ScheBo ELISA") and a new polyclonal particle-enhanced turbidimetric immunoassay ("Bühlmann PETIA"). The direct method comparison of two immunoassays was performed in 40 samples. Clinical comparisons were conducted against each other for the binary determination of "abnormal/normal" elastase levels and the three-way determination of "severe/moderate/no" EPI in 56 samples. The indirect comparison method used external quality assessment (EQA) data to compare the monoclonal and polyclonal immunoassays for PE, and additionally compare the monoclonal ScheBo ELISA to a monoclonal chemiluminescence immunoassay ("DiaSorin CLIA").

RESULTS

Precision in the series and intra-laboratory precision for Bühlmann PETIA met the manufacturer's specifications for the concentration range of limit/lower values and the range of normal values. The Bühlmann PETIA immunoassay on different analytical platforms yielded comparable results and nearly perfect agreement in the case of three-way classification (kappa = 0.89 with 95%CI from 0.79 to 1.00. ScheBo ELISA tends to generate higher values of pancreatic elastase than the Bühlmann PETIA; agreement between the methods was moderate in the case of binary classification (kappa = 0.43; 95% CI 0.25 to 0.62), and substantial in the case of three-way classification (kappa = 0.62; 95% CI 0.50 to 0.75). EQA data analysis showed a statistically significant difference between ScheBo ELISA and Bühlmann PETIA peer groups (p = 0.031), as well as the DiaSorin CLIA and ScheBo ELISA peer groups (p = 0.010).

CONCLUSION

The ScheBo ELISA and Bühlmann PETIA do not appear to be commutable in the analytical and clinical context. Our data address a discordance between different mono- and polyclonal immunoassays for pancreatic elastase and the potential of misclassification using its universal cut-off values in screening suspected patients for exocrine pancreatic insufficiency.

Impact of Pancreatic Enzymes on Enteral Fat and Nitrogen Absorption in Short Bowel Syndrome

OBJECTIVES

Patients with short bowel syndrome (SBS) can have a high morbidity rate. To minimize morbidity, enteral autonomy is the primary goal in clinical management of patients with SBS. This is often difficult to achieve because of significant malabsorption. To date, there are limited therapies that improve absorption in patients with SBS. The impact of pancreatic enzyme replacement treatment on enteral absorption has not been studied in this population and was the primary aim of this study.

SUBJECTS/METHODS

This was an interventional study in 11 subjects (6 pediatric subjects ages 4.0-17.9 years, 5 adult subjects 18-75 years) that compared enteral absorption in each subject before and after pancreatic enzyme medication (Creon). Coefficient of fat absorption (CFA) and coefficient of nitrogen absorption (CNA) were used as markers of enteral absorption of fat and protein, respectively.

RESULTS

There was no statistically significant mean change in CFA and CNA before and after pancreatic enzyme medication therapy. Six subjects demonstrated an increase in CFA and 8 subjects demonstrated an increase in CNA after the use of pancreatic enzyme medication therapy.

CONCLUSIONS

There was no statistically significant improvement in enteral fat and protein absorption in the cohort as a whole, though several subjects demonstrated an improvement. These results suggest that some patients with SBS may benefit from treatment with pancreatic enzymes. Further studies are needed to better evaluate the effect of pancreatic enzyme therapy on enteral absorption in subjects with SBS and to characterize factors that may predict a positive response.

Screening for gastrointestinal and pancreatic diseases

Diagnosis of chronic gastrointestinal and pancreatic diseases is challenging because patients generally present with nonspecific symptoms, such as abdominal pain and chronic diarrhea, some of which can last for many years. Although stool assays are more sensitive than serum assays, the former has unique limitations that healthcare providers should be aware of. One algorithm to screen for chronic gastrointestinal and pancreatic issues is to perform stool testing to assess inflammatory, watery (osmotic) and malabsorptive conditions. This chapter will discuss several stool-based screening tests, the major disorders they screen for and clinical performance. Sections on assay and sample limitations are also included. Stool testing can provide valuable diagnostic, prognostic and treatment response information if both the laboratory and clinician understand the benefits and limitations of these assays.

Clinical and Analytical Characterization of the DiaSorin and ScheBo Fecal Pancreatic Elastase 1 Assays

OBJECTIVES

Fecal pancreatic elastase (PE) assays are screening tests for exocrine pancreatic insufficiency (EPI). We analytically evaluated a new PE assay and retrospectively analyzed data from an academic hospital and reference laboratory to understand the clinical utility.

METHODS

Forty stool samples with different PE concentrations were tested on the ScheBo enzyme-linked immunosorbent assay (ELISA) versus DiaSorin LIAISON immunoassay; a simple-to-use extraction device was assessed. The cross-reactivity of porcine enzymes was investigated in the immunoassay. Charts of 207 patients with PE results less than 250 μg/g at an academic hospital were reviewed, and data were analyzed for 5136 patients with repeat PE results from a reference laboratory.

RESULTS

The LIAISON immunoassay gave comparable results to the ScheBo ELISA, with 87.5% agreement of PE results in classifying as sufficient, mild/moderate insufficiency, or severe insufficiency. The extraction device worked well compared with manual weighing, and no cross reactivity with porcine enzymes was observed. In agreement with prior studies, our clinical data suggested that PE assays were most useful in detecting severe EPI.

CONCLUSIONS

The new DiaSorin LIAISON immunoassay preforms similarly to the well-known ScheBo ELISA. Pancreatic elastase assays can help identify patients with severe EPI but are not as useful in classifying mild/moderate EPI.

The Changing Face of Cystic Fibrosis: An Update for Anesthesiologists

Cystic fibrosis (CF) is the most common fatal genetic disease in North America. While CF is more common among Whites, it is increasingly being recognized in other races and ethnicities. Although there is no cure, life expectancy has steadily improved, with the median survival exceeding 46 years in the United States. There are now more adults than children with CF in the United States. CF is caused by mutations in a gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein, expressed in many epithelial cells. More than 2100 CFTR mutations have been linked to CF, and newer CFTR modulator drugs are being used to improve the production, intracellular processing, and function of the defective CFTR protein. CF is a multisystem disease that affects primarily the lungs, pancreas, hepatobiliary system, and reproductive organs. Anesthesiologists routinely encounter CF patients for various surgical and medical procedures, depending on the age group. This review article focuses on the changing epidemiology of CF, advances in the classification of CFTR mutations, the latest innovations in CFTR modulator therapies, the impact of the coronavirus disease pandemic, and perioperative considerations that anesthesiologists must know while caring for patients with CF.

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.

Nutrition in cystic fibrosis: From the past to the present and into the future

Nutritional management is an integral part of multidisciplinary care for persons with cystic fibrosis. This review will look at how nutrition care has evolved over time. In addition, we will look at how some newer therapies impact nutrition care.

Pancreatic Function in Chronic Pancreatitis: A Cohort Study Comparing 3 Methods of Detecting Fat Malabsorption and the Impact of Short-term Pancreatic Enzyme Replacement Therapy

OBJECTIVES

Reliable pancreatic function tests in patients with chronic pancreatitis (CP) are needed. This cohort study identified malabsorption in people with CP compared with healthy people and then investigated short-term pancreatic enzyme replacement therapy (PERT) and fat malabsorption, nutritional status, and quality of life (QOL).

METHODS

Subjects with CP were evaluated before and after PERT and compared with the healthy cohort using coefficient of fat absorption (CFA), stool bomb calorimetry, and the malabsorption blood test (MBT). Anthropometrics, micronutrients, and QOL data were collected. Group means at baseline and after PERT were analyzed.

RESULTS

The 24 subjects with CP had greater stool energy loss (5668 cal/g [standard deviation {SD}, 753] vs 5152 cal/g [SD, 418], P < 0.01), reduced triglyceride absorption (MBT, 8.3 mg·h/dL [SD, 4.3] vs 17.7 mg·h/dL [SD, 10.3], P < 0.001), lower fat intake, and poorer QOL. Differences in CFA were not significant (90.9% [SD, 12.8] vs 95.4% [SD, 9.3]). After PERT, triglyceride absorption (Δ = 1.7 [SD, 3], P < 0.05) and QOL increased.

CONCLUSIONS

The MBT detected changes in triglyceride absorption in the absence of CFA changes. The MBT may be helpful in guiding PERT initiation in patients with CP before significant morbidity.

Exocrine pancreatic insufficiency: prevalence, diagnosis, and management

Exocrine pancreatic insufficiency (EPI) is a condition caused by reduced or inappropriate secretion or activity of pancreatic juice and its digestive enzymes, pancreatic lipase in particular. EPI can result in clinical manifestation and biochemical alterations causing reduced quality of life and life-threating complications. EPI is common in pancreatic disorders, where it should be suspected and actively investigated, and in many extrapancreatic conditions. There are various tests available to diagnose EPI, with indirect, noninvasive ones, such as concentration of fecal elastase being more commonly employed. Administration of pancreatic enzymes replacement therapy remains the mainstay of EPI treatment. The present review article will discuss current evidence regarding the prevalence of EPI, the available tests to diagnose it and its treatment.

Psychometric evaluation of a patient-reported outcome measure in pancreatic exocrine insufficiency (PEI)

BACKGROUND/OBJECTIVES

Pancreatic exocrine insufficiency (PEI) is commonly caused by chronic pancreatitis (CP) or cystic fibrosis (CF). There are no PEI-specific patient-reported assessments of symptoms and impacts. The PEI Questionnaire (PEI-Q) was developed through qualitative research with PEI patients and expert clinical input. This study evaluated the psychometric properties of the PEI-Q.

METHODS

162 PEI patients (CF = 71 and CP = 91), 62 diarrhoea-specific irritable bowel syndrome (IBS-D) patients and 60 healthy controls completed the 26-item PEI-Q and the Gastrointestinal Quality of Life Index (GIQLI) at baseline. PEI patients completed the measures again two weeks later to assess the test-retest reliability of the PEI-Q. Analyses supported item reduction and scoring algorithm development, followed by psychometric evaluation.

RESULTS

Over 90% of PEI patients completed at least 23 of the 26 items at baseline. Item responses and clinical relevance supported retention of 18 items. Factor analysis supported a three-factor solution (abdominal symptoms, bowel movements, impacts) with adequate model fit. PEI-Q scores had good internal consistency (Cronbach's alpha: 0.77-0.82) and test-retest reliability (ICC: 0.73-0.87). Correlations between PEI-Q and GIQLI supported convergent validity. Known-groups and receiver operating characteristic analyses demonstrated that PEI-Q scores discriminated (p < 0.001) between differing PEI severities, and PEI patients and controls.

CONCLUSIONS

The PEI-Q has good validity and reliability. Results indicate that the PEI-Q could be used to aid identification and diagnosis of PEI, assist in the management of patients already diagnosed with PEI, ensuring correct and optimum treatment as well as enhance patient-clinician communication.

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.

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.

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.

Maintenance of nutritional status in patients with cystic fibrosis: new and emerging therapies

Poor clinical outcomes in cystic fibrosis are often associated with undernutrition. Normal growth and development should be achieved in cystic fibrosis, and nutritional counseling is paramount at all ages. Prevention and early detection of growth failure is the key to successful nutritional intervention. The advance in nutritional management is certainly one factor that has contributed to the improved survival in recent decades. This review outlines the major nutritional parameters in the management of the patient with cystic fibrosis, including recent advances in pancreatic enzyme replacement therapy and fat-soluble vitamin therapy. There are sections on complicated clinical situations which directly affect nutrition, for example, before and after lung transplantation, cystic fibrosis-related diabetes, and bone health.

Partial pancreatic resection for pancreatic malignancy is associated with sustained pancreatic exocrine failure and reduced quality of life: a prospective study

OBJECTIVES

Pancreatic resection for cancer may produce pancreatic exocrine insufficiency (PEI), which is poorly understood. This study examined the coefficient of fat absorption (CFA), symptoms, quality of life (QoL) and the accuracy of faecal elastase-1 (FE-1) measurement to predict PEI.

METHODS

Forty patients were analysed following resection for pancreatic malignancy. The primary endpoint was PEI diagnosis defined by CFA <93%; secondary endpoints were PEI diagnosis using FE-1 <200 μg/g, body mass index (BMI), and symptom and QoL analysis. Interventions were 3-day stool collection, EORTC QLQ-C30 (version 1) questionnaire and patient's diary, at 6 weeks and 3, 6 and 12 months after surgery.

RESULTS

CFA <93% was present in 67% of patients at 6 weeks and in 55% at 12 months. PEI using FE-1 was present in 77 and 83% of patients, respectively. No significant changes between time-points were observed. Sensitivity, specificity, PPV, NPV and accuracy for FE-1 in detecting CFA <93% were 91, 35, 70, 71 and 70%, respectively. CFA and FE-1 levels were uncorrelated. Overall, QoL increased at 6 (p = 0.0212) and 12 (p < 0.0001) months after surgery, mainly driven by physical, role and social functioning, and by appetite. Importantly, however, BMI and symptoms were unaffected by PEI, which suggests a subclinical presentation; such patients had attributes indicating poorer QoL (notably insomnia, p = 0.0012).

CONCLUSIONS

PEI was common and sustained following resection and not associated with significant symptoms. These patients had a tendency toward poorer QoL. FE-1 is a poor surrogate for diagnosing impaired fat absorption. Postoperative pancreatic enzyme replacement should be considered more routinely. and IAP.

Nutritional considerations in patients with cystic fibrosis

Nutritional status is strongly associated with pulmonary function and survival in cystic fibrosis patients. Attainment of a normal growth pattern in childhood and maintenance of adequate nutritional status in adulthood represent major goals of multidisciplinary cystic fibrosis centers. International guidelines on energy intake requirements, pancreatic enzyme-replacement therapy and fat-soluble vitamin supplementation are of utmost importance in daily practice. The present review summarizes the most up-to-date information on early nutritional management in newly diagnosed patients and evaluates the benefits of aggressive nutritional support, assessment of nutritional status, recommendations for nutrition-related management in pancreatic-insufficient patients and the possible therapeutic impact of fat intake modulation upon inflammatory status.

Cystic fibrosis

Cystic fibrosis is the most common lethal genetic disease in white populations. The outlook for patients with the disease has improved steadily over many years, largely as a result of earlier diagnosis, more aggressive therapy, and provision of care in specialised centres. Researchers now have a more complete understanding of the molecular-biological defect that underlies cystic fibrosis, which is leading to new approaches to treatment. One of these treatments, hypertonic saline, is already in use, whereas others are in advanced stages of development. We review clinical care for cystic fibrosis and discuss recent advances in the understanding of its pathogenesis, implementation of screening of neonates, and development of therapies aimed at treating the basic defect.

Newborn screening for cystic fibrosis

Newborn screening (NBS) for cystic fibrosis (CF) has evolved considerably from its beginnings. We review the early history of NBS in the USA and the evolution of CF NBS from its conception in observational studies, to the development of mass-screening methodology in the 1970s, and to its early applications in the USA and other countries. We review the development of current CF NBS algorithms, particularly the development of those used in the Wisconsin randomized controlled trial, and discuss the comparative utility of different algorithms. We also discuss the identified nutritional and respiratory benefits of CF NBS, discuss treatment strategies for newborns identified with CF, and also discuss opportunities for slowing the progression of this disease.

Evaluation of a fecal pancreatic elastase-1 enzyme-linked immunosorbent assay: Assessment versus an established assay and implication in classifying pancreatic function

BACKGROUND

Disagreement continues regarding 2 fecal pancreatic elastase-1 (PE-1) ELISAs and their respective capabilities to assess pancreatic function.

METHODS

The BioServ Diagnostics polyclonal PE-1 ELISA was validated and its performance characteristics compared to the previously validated ScheBo Biotech monoclonal PE-1 ELISA. Split sample study results were analyzed by Deming regression and Bland-Altman plot analysis. Data mining was utilized to explore PE-1 distribution and evaluate PE-1 and fecal fat correlation.

RESULTS

Analysis demonstrates limited quantitative agreement; slope=0.9640, intercept=10.787, R(2)=0.633. Means were 228.8 and 226.2 microg PE-1/g stool for the polyclonal and monoclonal assays respectively. Bland-Altman analysis showed 91% of paired values within 2 SD of their means. There was good qualitative agreement when interpreted against established intervals with 91% of results equivalent in pancreatic function classification. The remaining 9% varied by one classification level with no bias evident. The distribution of PE-1 concentrations (n=400, 0-25 years) classified 78% of subjects with normal pancreatic function, 7% with moderate pancreatic insufficiency and 15% with severe insufficiency. There was little agreement between PE-1 and fecal fat results.

CONCLUSIONS

The polyclonal PE-1 ELISA is an acceptable alternative to the monoclonal PE-1 ELISA. PE-1 is a potential substitute for fecal fat for evaluating pancreatic function.