Introduction
Pancreatic function tests are a valuable tool to measure and diagnose both the disease of the exocrine pancreas (reduced pancreatic secretions) and exocrine pancreatic insufficiency (malabsorption). The function of the pancreas is to produce digestive enzymes, break down protein, carbohydrates, and fat, and form hormones such as insulin and glucagon. The pancreatic functioning tests help to diagnose and monitor various pancreatic disorders, including pancreatitis (swelling or inflammation of the pancreas), pancreatic cancer, and diabetes mellitus (increased blood sugar levels). This article highlights the types of pancreatic function tests, indications, and symptoms of pancreatic malfunction.
What Is a Pancreatic Function Test?
A number of tests have been performed to assess the function of the pancreas (a small organ located in the abdomen). The pancreatic function test is one of the crucial tests to determine any disruption in pancreatic function and to diagnose diseases related to the pancreas such as chronic pancreatitis (swelling and infection in the pancreas).
What Are the Types of Pancreatic Function Tests?
Pancreatic function test can be divided into two types:
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Direct Test of Pancreatic Function: The direct pancreatic test follows the principle of collecting pancreatic secretions to determine the capacity of secretion of the pancreas by measuring the amount of secretions. It is important to use secretagogues (agents that increase secretions) to stimulate the pancreas during the test. The secretion is collected in a tube that is connected to the stomach in the duodenum region. Lagerlof was the first person to describe the use of a secretagogue agent for pancreatic stimulation during the test. This test was further modified by the Japanese Society of Gastroenterology by a change in secretagogue agents and timing as well as the amount of collection. This test was recommended as a gold standard test for the assessment of exocrine (exocrine gland that helps in the secretion of digestive enzymes) pancreatic function (disease of exocrine pancreas).
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Indirect Pancreatic Function Test: The indirect pancreatic function test is based on the principle of assessing pancreatic enzyme function in the intestine. It includes the measurement of by-products of digestion and particles of undigested food in the urine or blood. This test is reliable only in cases where indigestion is observed. This test is used in diagnosing exocrine pancreatic insufficiency.
What Are the Common Pancreatic Function Tests?
A few common pancreatic function tests are:
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Blood Test: Increased serum amylase and lipase levels in the blood may indicate swelling of the pancreas. Abnormal blood sugar levels are indicative of pancreatic dysfunction.
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Stool Test: The stool test helps measure elastase levels - an enzyme released by the pancreas. Decreased elastase levels are indicators of pancreatic insufficiency. Reduced elastase levels are more commonly seen in conditions like cystic fibrosis (a life-threatening disorder that damages the digestive system and lungs) and chronic pancreatitis.
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Imaging Studies: Endoscopic retrograde cholangiopancreatography or ERCP visualizes the pancreas, bile ducts, and pancreatic ducts. This imaging procedure helps to rule out any structural abnormalities, tumors, or blockages. Magnetic resonance imaging (MRI) and computed tomography scans (CT scans) help to diagnose any pancreatic disease or defects in the surrounding structure.
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Glucose Tolerance Test: This pancreatic function test helps to evaluate the pancreas' ability to regulate blood sugar levels by measuring glucose levels before and after administration of a glucose solution. It helps diagnose increased blood sugar levels and assess insulin secretion from the pancreas. An increase in blood sugar levels helps to rule out pancreatic dysfunction.
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Pancreatic Biopsy: Biopsy procedures such as endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) involve using an ultrasound probe to guide the needle to collect tissue samples from the pancreas for analysis. It is helpful in diagnosing pancreatic tumors or lesions.
Interpreting the results of pancreatic function tests requires clinical expertise and consideration of the patient's medical history and symptoms. These tests are essential for diagnosing pancreatic diseases early, monitoring disease progression, facilitating timely interventions, and improving patient outcomes. Overall, pancreas function tests are valuable tools in the armamentarium of clinicians or healthcare professionals for diagnosing and managing a wide range of pancreatic diseases and planning treatment decisions, contributing to better patient outcomes and QOL (quality of life).
What Are the Functions of Pancreatic Dysfunction?
The signs and symptoms associated with pancreatic dysfunction are:
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Fever.
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Weight loss.
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Stomach ache.
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Foul-smelling stool.
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Severe stomach pain.
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Lower chest pain.
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Vomiting and nausea.
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Increased thirst (mostly seen in diabetic patients).
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Frequent urination is seen in diabetic patients.
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Malabsorption or indigestion.
When Is a Pancreatic Function Test Indicated?
Pancreatic function tests are advised if there is,
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Impaired insulin secretion.
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Family history of pancreatic disease.
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Chronic alcoholism (long-term alcohol intake).
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Cholelithiasis (formation of the gall bladder stones).
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Duodenitis (inflammation of the duodenum).
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Bacterial or viral infections.
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High cholesterol levels.
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Hormonal disorders.
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Chronic pancreatitis (inflammation of the pancreas).
How Is the Endoscopic Pancreatic Function Test Performed?
An ETFT or endoscopic pancreatic function test is performed under proper sedation. Approximately 0.2 micrograms of human secretin (secretagogues agent) per kilogram of body weight is given intravenously (IV). The endoscope is positioned in the duodenum. The secretion from the duodenum is collected in a tube for 15 min (minutes), 30 min, 45 min, and 60 min after administration of the secretin. The collected sample is then sent to the laboratory for analysis of the concentration of bicarbonate. Levels of bicarbonate that are more than 80 milliequivalent per liter are considered abnormal. This test helps in ruling out the disease.
Conclusion
Pancreas function tests play a crucial role in diagnosing pancreatic diseases and monitoring their progression. Various tests such as pancreatic enzyme levels, glucose tolerance tests, and imaging studies help in assessing pancreatic function. These tests not only aid in early detection but also guide treatment decisions and prognostication. However, challenges remain in standardizing testing protocols and interpreting results accurately. Future research efforts should focus on refining existing tests, exploring novel biomarkers, and integrating multi-modal approaches for a comprehensive evaluation of pancreatic function. Ultimately, enhancing our understanding and diagnostic capabilities in pancreatology will contribute to improved patient outcomes and better management of pancreatic disorders.
