Glucagon is a hormone that is produced by the pancreas. It is often thought of as having the opposite effect of insulin. While insulin works to reduce high levels of glucose in the bloodstream, glucagon helps to ensure that glucose levels do not drop too low. When glucose levels in the bloodstream drop, the pancreas releases glucagon. Once in the bloodstream, it stimulates the breakdown of glycogen, which is stored in the liver. Glycogen is broken down into glucose and released into the bloodstream to maintain normal blood glucose levels and cellular function.
The glucagon test is used to measure the amount of glucagon in a patient’s bloodstream.
Why Is the Test Ordered?
Glucagon is an important hormone required in the regulation of normal blood glucose levels. Patients who experience wide fluctuations in their blood glucose levels, including hypoglycemia (low blood sugar), may have problems with glucagon regulation. In addition to testing for hypoglycemia, your physician may order a glucagon test if the following symptoms are present:
- mild diabetes
- a skin rash known as necrolytic migratory erythema
- unexplained weight loss
These symptoms are commonly associated with pancreatic disorders that result in overproduction of glucagon. It is important to note that given the unique specificity of the symptoms, the glucagon test is not routinely ordered as part of a patient’s regular annual physical examination.
How Is the Test Administered?
The glucagon test is performed on a blood sample, typically drawn from a patient in a clinical setting. The blood sample is commonly taken from an arm vein using a needle. The blood will be collected in a tube and will be sent to a lab for analysis. Once the results are reported from the lab, your doctor will be able to provide you with more information about the results and what they mean.
Preparation for the Test
In many instances, there are no specific preparations needed for the glucagon test. Depending on the patient’s existing health conditions and the purpose of the test, specific instructions for fasting may be provided by your physician. Fasting requires the patient to abstain from food for a certain period of time before the test is performed. Patients may be required to fast eight to 12 hours before the test is administered.
What Are the Advantages of the Test?
The principle advantage of the glucagon test is that it can help physicians identify the presence of diseases associated with excess glucagon production. Although diseases caused by abnormal glucagon levels are rare, elevated levels are often associated with specific health issues. For instance, elevated glucagon levels may be the result of a pancreatic tumor callled a glucagonoma.
The tumor produces excess glucagon that can result in the development of diabetes. In patients with glucagonoma, additional symptoms may be present. These include unexplained weight loss and necrolytic migratory erythema. For patients with mild diabetes, this test will rule out the presence of glucagonoma as the underlying cause of the disease.
The glucagon test may also be used to measure glucose control in patients who have developed type 2 diabetes or in patients who may be insulin resistant. In these patients glucagon levels are typically high. Effective control of blood sugar levels will help the patient to maintain normal levels of glucagon.
What Are the Risks of the Test?
The glucagon test is a blood test that carries with it minimal risks for the patient. The risks of the test are common to all blood tests and include the following:
- difficulty obtaining a sample, resulting in the need for multiple needle sticks
- excessive bleeding at the needle site
- the accumulation of blood under the skin, known as a hematoma
- infection at the site of needle entry into the skin
What are the Desired Results?
In normal glucagon level range is 50 to 100 pg/mL. Normal value ranges may vary slightly among different laboratories and different labs may use different measurements. Results from the glucagon test must be considered in conjunction with other blood and diagnostic tests to make a formal diagnosis.