Abacus
Diagnostics
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Exocrine Pancreatic Insufficiency itself is relatively uncommon however there is a high frequency in patients with Cystic Fibrosis and adults with alcoholism and others with chronic pancreatitis. It is also included in the differential diagnosis of malabsorption and steatorrhoea. Malabsorption and maldigestive syndromes represent a common sign of advanced pancreatic, intestinal and hepato-biliary diseases.
Previously there has been no specific indirect test available in Australia for the diagnosis of exocrine pancreatic insufficiency. The diagnosis is made by clinical assessment plus the use of three day faecal fat analysis. The sensitivity of faecal fat determination is poor and ranges from 45% to 100%. Specificity is also low with false positive results being reported in a variety of non-pancreatic diseases including: liver cirrhosis, coeliac disease, Crohn’s disease and other gastrointestinal disease associated with diarrhoea or malabsorption due to small bowel disease.
The assay measures pancreatic elastase, which is a proteolytic pancreas-specific enzyme of the acid elastase family. It is synthesised by the pancreatic acinar cells along with other pancreatic digestive enzymes (Fowler 1998). The assay is an ELISA, which uses two monoclonal antibodies to human elastase 1. Pancreatic elastase is extracted from a faecal sample in phosphate buffered saline. The specimen used is a single random stool sample. The sample is stable for 24 hours at 4-8°C. Only approximately 100mg sample is required. Sample is homogenised into an extraction buffer and is stable in this solution for up to 24 hours at 4-8°C. Diluted samples are stable at –20°C for up to 12 months.
Significant Advantages
PE1 offers the following advantages for the diagnosis of exocrine pancreatic insufficiency and differential diagnosis of malabsorption and steatorrhoea. :
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Relatively inexpensive, simple to perform, non-invasive, highly sensitive and specific, reproducible. (Soldan et al 1997) |
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High suitability for paediatric patients (Wallis et al 1997) |
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Almost absolute pancreatic specificity (Gullo et al 1999) |
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Strong correlation with the gold standard for the diagnosis of exocrine pancreatic insufficiency (invasive secretin-pancreozymin (cholecystokinin) test)( Loeser et al 1996, Stein & Caspary 1997 ) |
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Results are not effected by pancreatic enzyme replacement therapy therefore there is no requirement for patients to stop substitution therapy prior to providing a sample (Gullo et al 1999, Stein et al 1995) |
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Ease of patient collection and compliance (Stein et al 1995) |
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Much greater probability of a high quality sample (Loeser et al 1996, Gullo et al 1999) |
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Significant improvement over current tests which are unpopular with both patients and laboratory staff (Blake 1999) |
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Limited application in cases of mild Chronic Pancreatitis, however these patients rarely even display clinical indication of disease (Dominguez-Munoz et al 1995) |
The pancreas of dogs secretes a digestive enzyme, which is homologous to the human pancreatic elastase 1. The assay measures pancreatic elastase, which is a proteolytic pancreas-specific enzyme of the acid elastase family. It is synthesised by the pancreatic acinar cells along with other pancreatic digestive enzymes (Fowler 1998). The assay is an ELISA that uses a monoclonal antibody, which only recognises canine pancreatic elastase 1 ( PE1).
Clinical Indications
Weight loss and maldigestion (usually presenting as steatorrhoea) are two of the main clinical symptoms suggestive of pancreatic exocrine insufficiency in dogs. Diagnosis or exclusion of pancreatic insufficiency is important as an indicator of :
Pancreatic Acinar Atrophy, Pancreatic Cancer, Chronic Pancreatitis, Parasites or Stones
Sample Requirements
The specimen used is a single random stool sample.
The sample is stable for up to three days at 4-8°C. Only approximately 100mg sample is required. Sample is homogenised into an extraction buffer and is stable in this solution for up to 24 hours at 4-8°C. Diluted samples are stable at –20°C for up to 12 months.
Benefits
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PE1 is not degraded during intestinal transit therefore its faecal concentration reflects pancreatic exocrine function. |
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The marker is highly specific for canine pancreatic function |
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Highly sensitive marker of chronic pancreatic insufficiency |
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Faecal sample offers ease of collection over serum |
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Small random faecal sample only is required |
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High stability of pancreatic elastase means a sample is stable for up to 3 days at 2-8C and for up to a year at –20C |
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The marker is not diet dependant and therefore, in contrast to the cTLI test, fasting for 12 hours is not required |
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Digestive enzyme substitution therapy has no influence on the determination of canine PE1 |
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Simple, non-radioactive assay which can replace the cTLI while maintaining equivalent reliability |
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Use of a more stable ELISA technology offers much longer expiration and reduces waste |