The Nature and Purpose of the Pancreatic Function Test
The pancreas is a spongy organ shaped rather like a flattened pear that is situated in the upper left quadrant of the abdomen behind the stomach. Between 15 and 25 cm in length, it is unique in that it combines the functions of both an endocrine and an exocrine gland. That is to say it secretes chemicals both into the bloodstream and into the gastrointestinal tract. In the former case, these secretions consist of the two hormones known as insulin and glucagon that act, respectively, to lower or to raise the level of glucose in the blood. When this balance is disturbed for any reason, the affected individual will display the condition known as diabetes.
The organ’s exocrine secretions assist with the digestion of fats, carbohydrates and proteins and consist of a number of enzymes. The most important of these are trypsin and chymotrypsin that act to digest proteins while lipase and amylase are responsible for the breakdown of fats and carbohydrates respectively. Normal and abnormal pancreatic function can be evaluated with a variety of tests. While insulin and glucagon assays are possible, the detection of diabetes generally requires no more than an initial assay of a patient’s fasting blood sugar level to raise awareness followed, where indicated, by an oral glucose tolerance test (OGTT) in order to confirm the diagnosis.
When it is required to determine enzyme function, there are a number of possible procedures and the most common reason for performing them is to confirm or to exclude the condition known as pancreatitis in which the patient displays fever and the organ becomes swollen, tender, and inflamed – symptoms that are usually accompanied by abnormal exocrine activity. While the presence of such abnormalities can be determined by various analyses performed on blood serum, evidence may also be detected in stool samples. In addition, the techniques of CT scanning using contrast dyes, abdominal ultrasound, endoscopic examinations, and magnetic resonance imaging (MRI) are all valuable adjuncts that are commonly used today as a means to confirm and enhance the findings of chemical and immunological pancreatic function tests.
Routine blood tests to measure the levels of amylase and lipase are a common starting point for the detection of pancreatitis while more elaborate tests to evaluate the organ’s functionality directly introduce secretin or cholecystokinin into the duodenum where a healthy organ will respond by producing alkaline bicarbonate ions normally used to neutralise stomach acids. Analysis of duodenal fluid over a period will confirm or exclude malfunction while abnormal levels could indicate pancreatitis, cystic fibrosis, or cancer.
The measurement of another enzyme produced by the pancreas can be applied to faecal samples and is proving to be a quick and relatively simple means to evaluate the organ’s efficiency. It uses the technique known as enzyme-linked immunosorbent assay or ELISA to detect levels of the enzyme elastase and offers an effective and inexpensive alternative to more complex diagnostic procedures that makes it an ideal choice for first-line screening purposes.
In South Africa, a full range of quality products for use in pancreatic function tests on blood and faecal samples is available from IEPSA – widely accepted as the nation’s leader in the supply of diagnostic reagents for more than 35 years.