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insulin in serum

Reference interval: - free insulin (see Procedure:) a) adult: < 17 uIU/mL (< 118 pmol/L) b) infants & prepubertal children: < 13 uIU/mL (< 90 pmol/L) Increases: 1) pharmaceutical agents -> in vivo -> acetohexamide, albuterol, amino acids, calcium gluconate (newborn), chlorpropamide, cyproheptadine (non-diabetics), danazol, fructose, glucagon, glucose, growth hormone, levodopa, medroxyprogesterone, niacin, oral contraceptives, pancreozymin (IV), phentolamine (IV), prednisolone, quinidine, secretin (IV), spironolactone, sucrose, terbutaline, tolazamide, tolbutamide 2) clinical disorders a) insulinoma b) diabetes mellitus, type 2 c) liver disease d) acromegaly e) Cushing's syndrome f) myotonic dystrophy g) familial fructose & galactose intolerance h) obesity i) surreptitious use of insulin or sulfonylureas Decreases: 1) pharmaceutical agents a) in vivo -> beta-blockers, asparaginase, bezafibrate, calcitonin, chlorpropamide, cimetidine, clofibrate, diazoxide, doxazosin, ethacrynic acid, ethanol, ether, furosemide, metformin, nifedipine, phenformin, phenobarbital, phenytoin, thiazides, tolbutamide (some patients) b) chemical interferences -> hemolysis, heparin (some assays) 2) clinical disorders a) diabetes mellitus, type 1 b) hypopituitarism Procedure: - free (bioactive) insulin is measured after polyethylene glycol (PEG) precipitation of anti-insulin antibodies & their bound insulin - total insulin may be measured by acidification of the sample to dissociate insulin from endogenous antibodies before treatment with PEG - if insulin antibodies are not present, free & immunoreactive insulin assays are the same - simultaneous measurement of C-peptide is suggested to evaluate hypoglycemia due to surreptitious use of insulin Methods: 1) RIA 2) immunometric assay (2-site) -> no cross reaction with pro-insulin Specimen: 1) serum 2) separate from cells as soon as possible 3) freeze immediately 4) store frozen Notes: - little clinical value except for evaluation of fasting hypoglycemia

Related

C-peptide in serum

General

special chemistry test

References

  1. Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
  2. Insulin, Fasting Laboratory Test Directory ARUP: 70063
  3. Insulin, 30 Minutes Laboratory Test Directory ARUP: 70064
  4. Insulin, 60 Minutes Laboratory Test Directory ARUP: 70066
  5. Insulin, 90 Minutes Laboratory Test Directory ARUP: 70067
  6. Insulin, 120 Minutes Laboratory Test Directory ARUP: 70068
  7. Insulin, Random Laboratory Test Directory ARUP: 70107
  8. Mini Panel of 2 tests: Insulin Free . Total Insulin Laboratory Test Directory ARUP: 70155
  9. Mini Panel of 2 tests: Insulin, Fasting . Proinsulin Laboratory Test Directory ARUP: 70256
  10. Insulin, Veterinary Laboratory Test Directory ARUP: 70690

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endocrinology 7 analyte panel glucose/insulin in serum/plasma insulin-induced C-peptide suppression panel proinsulin/insulin in serum/plasma