Due to the deep-seated location and the high incidence of complications following biopsies, and despite the fact that histological studies provide the most conclusive evidence of chronic pancreatitis, the microscopic examination of biopsied tissue is not a practical means with which to test pancreatic function. Instead, the preferred approach has been to rely upon indirect methods as the means to evaluate the efficiency of this important organ.

The pancreas is a glandular organ that forms a part of the digestive system in vertebrates. Located in the abdominal cavity and to the rear of the stomach, it is responsible for a combination of endocrine and exocrine secretions. The former are the hormones insulin and glucagon, which are delivered directly into the bloodstream, whilst the latter are digestive enzymes secreted externally into the duodenum.

Abnormal activity can lead to anomalous levels of either or both types of secretion. In the case of endocrine secretions, evaluating their concentration in blood serum can often provide a conclusive means with which to confirm or exclude a diagnosis, whilst the study of digestive secretions present in faeces also offers valuable diagnostic information.

Inadequate pancreatic function can lead to reduced insulin levels and diabetes, but fortunately, a simple blood glucose measurement makes more complex hormone assays unnecessary. A high fasting level of blood glucose is a strong indicator which may be confirmed with a glucose tolerance test.

Assays of various exocrine secretions, which include the enzymes trypsin, lipase and amylase, can provide us with information regarding any abnormalities in the organ’s digestive activities. Faecal tryptic activity and serum amylase levels were among the first investigation used as an aid to the diagnosis of pancreatitis. The earliest basis for such measurements was to perform an indirect assessment based on the effect of the enzyme upon its specific substrate. For instance, increasing dilutions of faecal matter incubated in the presence of gelatine results in liquefaction when trypsin levels are sufficiently high, so the greater the dilution at which liquefaction occurs, the greater the concentration of trypsin. Similar treatment of serum in the presence of a starch substrate, and measuring any undigested residue with iodine, forms the basis for measuring amylase activity.

In recent years, the basis of the pancreatic function test has undergone a marked transformation. The change has largely been motivated by the need for procedures that are both quicker and more specific than previous methods. In particular, it was required to provide a means with which to screen patients for malignant tumours of this organ that, if indicated, would permit early intervention and the correspondingly increased chance of a successful treatment.

A new procedure developed in the late ‘60s and early ‘70s, and known as the enzyme-linked immunosorbent assay or ELISA, provided a means to detect and quantify a range of organic compounds that includes proteins, peptides, hormones and antibodies. ELISA has been successfully applied for many purposes, including the detection of allergens in foodstuffs.

The adaptation of this technology has allowed the detection of specific biomarkers known to be associated with malignant and precancerous conditions of the pancreas, in body fluids. It provides a valuable addition to the diagnostic tools of oncologists. This rapid, reliable and relatively inexpensive pancreatic function test is available in South Africa from IEPSA.

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