Synonym/Acronym
N/A
Rationale
To evaluate the amount of circulating glucagon toward diagnosing diseases such as hypoglycemia, glucagon secreting tumor, pancreatic cancer, or inflammation.
Patient Preparation
There are no fluid, activity, or medication restrictions unless by medical direction. Instruct the patient to fast for at least 12 hr before specimen collection for baseline values. Patients with diabetes should have good glycemic management before testing.
Normal Findings
Method: Radioimmunoassay.
| Age | Conventional Units | SI Units (Conventional Units × 1) |
|---|
| Cord blood | 0–215 pg/mL | 0–215 ng/L | | Newborn | 0–1,750 pg/mL | 0–1,750 ng/L | | Child | 0–148 pg/mL | 0–148 ng/L | | Adult | 20–100 pg/mL | 20–100 ng/L |
|
Study type: Blood collected in chilled, lavender-top [EDTA] tube; related body system: Endocrine system. Specimen should be transported tightly capped and in an ice slurry.
Glucagon is a peptide hormone secreted by the alpha cells of the islets of Langerhans in the pancreas in response to hypoglycemia. This hormone acts primarily on the liver and muscles to release glucose from glycogen stores and if needed, to activate a pathway, called gluconeogenesis, by which the liver converts amino acids to glucose. Glucagon, along with other hormones, such as catecholamines, adrenocorticotropic hormone, growth hormone, and corticosteroids, stimulate release of an enzyme called hormone-sensitive lipase, which participates in the oxidation of stored fatty acids such as triglycerides to basic glycerol components used to produce glucose. Glucagon increases glucose levels, insulin works in opposition to glucagon by decreasing circulating glucose levels.
People with type 1 diabetes may use injectable glucagon to raise the blood sugar when a severe hypoglycemic emergency occurs, such that they are rendered unable to swallow liquid or food containing glucose due to sleepiness, loss of consciousness, or related to seizure activity.
Patients with glucagonoma, a tumor almost always localized in the pancreas, have values greater than 500 pg/mL. Values greater than 1,000 pg/mL are diagnostic for this condition. Glucagonoma causes three different syndromes:
- Syndrome 1: A characteristic skin rash, diabetes or impaired glucose tolerance, weight loss, anemia, and venous thrombosis (For additional information regarding screening guidelines and management of diabetes, refer to the study titled “Glucose.”)
- Syndrome 2: Severe diabetes
- Syndrome 3: Multiple endocrine neoplasia
A dramatic increase in glucagon occurring soon after kidney transplantation may indicate organ rejection. In the case of kidney transplant rejection, glucagon levels increase several days before an increase in creatinine levels.
Glucagon deficiency can be confirmed by measuring glucagon levels before and after IV infusion of arginine 0.5 g/kg. Glucagon deficiency is confirmed when levels fail to rise 30 to 60 min after infusion. Newborn infants of mothers with diabetes have impaired glucagon secretion, which may play a role in their hypoglycemia.
Factors That May Alter the Results of the Study
- Drugs and other substances that may increase glucagon levels include amino acids (e.g., arginine), cholecystokinin, danazol, gastrin, glucocorticoids, insulin, and nifedipine.
- Drugs and other substances that may decrease glucagon levels include atenolol, pindolol, propranolol, secretin, and verapamil.
- Recent radioactive scans or radiation within 1 wk before the test can interfere with test results when radioimmunoassay is the test method.
Increased In
Glucagon is produced in the pancreas and excreted by the kidneys; conditions that affect the pancreas and cause cellular destruction or conditions that impair the ability of the kidneys to remove glucagon from circulation will result in elevated glucagon levels.
- Acromegaly(related to stimulated production of glucagon in response to growth hormone)
- Acute pancreatitis (related to decreased pancreatic function)
- Burns(related to stress-induced release of catecholamines, which stimulates glucagon production)
- Chronic kidney disease (related to decreased renal excretion)
- Cirrhosis (pathophysiology is not well established)
- Cushing syndrome (evidenced by overproduction of cortisol, which stimulates glucagon production)
- Diabetes (unmanaged) (pathophysiology is not well established)
- Glucagonoma (related to excessive production by the tumor)
- Hyperlipoproteinemia (pathophysiology is not well established)
- Hypoglycemia (related to response to decreased glucose level)
- Infection (related to feedback loop in response to stress)
- Kidney transplant rejection (related to decreased renal excretion)
- Pheochromocytoma (excessive production of catecholamines stimulates increased glucagon levels)
- Stress (related to stress-induced release of catecholamines, which stimulates glucagon production)
- Trauma(related to stress-induced release of catecholamines, which stimulates glucagon production)
Decreased In
Low glucagon levels are related to decreased pancreatic function.
- Chronic pancreatitis
- Cystic fibrosis
- Postpancreatectomy period
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
- Discuss how this test can assist in evaluating the hormone that participates in regulating blood sugar.
- Explain that a blood sample is needed for the test.
Potential Nursing Actions
- It is important that patients with diabetes have good glycemic management before the study.
- Identify the degree of glycemic management before the study.
After the Study: Implementation & Evaluation Potential Nursing Actions
Treatment Considerations
- Discuss information related to the clinical implications of the test results.
- Discuss how good glycemic management delays the onset and slows the progression of diabetic retinopathy, nephropathy, and neuropathy.
- Advise the patient to resume usual diet, as directed by the health-care provider.
- Discuss how increased glucagon levels may be associated with diabetes.
- Instruct the patient and caregiver to report signs and symptoms of hypoglycemia (weakness, confusion, diaphoresis, rapid pulse) or hyperglycemia (thirst, polyuria, hunger, lethargy).
Nutritional Considerations
- Abnormal results may be associated with diabetes.
- Discuss the nutritional management of diabetes.
- There is no “diabetic diet”; however, many meal-planning approaches with nutritional goals are endorsed by the American Diabetes Association.
- Patients who adhere to dietary recommendations report a better general feeling of health, better weight management, greater management of glucose and lipid values, and improved use of insulin.
- Variety of dietary patterns is beneficial for people with diabetes.
- Encourage consultation with a registered dietitian who is a certified diabetes educator.
Clinical Judgement
- Consider how to reinforce the seriousness of study findings to overall health and quality of life.
Follow-Up and Desired Outcomes