Measurement of serum insulin levels is used to diagnose insulinoma in combination with measurements of proinsulin and C-peptide and in the management of diabetes mellitus.
Insulin is a hormone secreted by the beta cells of the islets of the Langerhans pancreas. It regulates the metabolism and transport of carbohydrates, amino acids, proteins, and lipids and facilitates glucose uptake by adipose tissue and skeletal muscles. Insulin also stimulates the synthesis and storage of triglycerides and proteins. The secretion of insulin occurs when blood glucose levels rise. As blood glucose levels subsequently decrease, insulin secretion ceases.
Measurement of insulin can provide information on the existence of insulin resistance. If insulin levels are high with a normal or elevated blood glucose (sugar) concentration, the problem may be that the pancreas works harder than it needs to keep blood sugar under control. Insulin resistance is a feature of metabolic syndrome, a condition that increases the risk of coronary heart disease and type 2 diabetes.
Measurement of serum insulin levels is also used in the diagnosis of hypoglycaemic conditions and diabetes mellitus. Evaluation of insulin is sometimes useful in combination with a glucose tolerance test. In the case of pancreatic islet cell transplantation, monitoring insulin levels may be useful in assessing graft viability.
Possible Interpretations of Pathological Values
- Increase: Acromegaly, Beckwith-Wiedemann syndrome, b-cell adenoma, Cushing's syndrome, myotonic dystrophy, familial fructose and galactose intolerance, hyperinsulinism, hypoglycemia, insulin resistance, insulinoma, liver disease, insulin-independent diabetes mellitus, metabolic syndrome, nesidioblastosis, obesity, insulin overdose, pancreatic islet cell damage, pheochromocytoma. Medications: Albuterol, calcium gluconate, estrogen, fructose, glucagon, glucose, insulin, levodopa, medroxyprogesterone, oral contraceptives, prednisolone, quinine, quinidine, spironolactone, sucrose, terbutaline, tolazamide, tolbutamide.
- Decrease: Diabetes mellitus, hyperglycemia, pituitary gland dysfunction, diabetes due to pancreatectomy. Medications: beta-adrenergic blockers, asparaginase, calcitonin, cimetidine, diazoxide, ethacrynic acid, ethyl alcohol (ethanol), ether, ffurosemide, metformin, nifedipine, phenformin, phenobarbital, phenytoin, thiazide diuretics.
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
