Insulin

Indicate collection date and time on sample or requisition

INS

0.5mL Li Heparain Plasma (PST)

50 uL

Refrigerated

Room temperature: 4 hours at 20-25^oC Refrigerated: 2 days at 2-8°C Frozen: 6 months at ­20°C, Freeze only once.

Samples not labeled with first and last name and date of birth.
Grossly hemolyzed specimen.

Sun - Sat

Same day

Samples from patients treated with bovine, porcine or human insulin sometimes contain anti-insulin antibodies which can affect the test results.
Samples should not be taken from patients receiving therapy with high biotin (Vitamin B) doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration.

2.6-24.9 uIU/mL

Insulin is a peptide hormone that is secreted by the B cells of the pancreas and passes into circulation via the portal vein and the liver. Insulin is generally released in pulses, with the parallel glucose cycle normally about 2 minutes ahead of the insulin cycle. Circulating insulin has a half-life of 3-5 minutes and is preferentially degraded in the liver, whereas inactivation or excretion of proinsulin and C peptide mainly takes place in the kidneys.
 
Serum insulin determinations are mainly performed on patients with symptoms of hypoglycemia. They are used to ascertain the glucose/insulin quotients and for clarification of questions concerning insulin secretion, e.g. in the tolbutamide test and glucagon test or in the evaluation of oral glucose tolerance tests or hunger provocation tests. A disorder in insulin metabolism leads to massive influencing of a number of metabolic processes. A too low concentration of free, biologically active insulin can lead to the development of diabetes mellitus. Possible causes of this include destruction of the β cells (type I diabetes), reduced activity of the insulin or reduced pancreatic synthesis (type II), circulating antibodies to insulin, delayed release of insulin or the absence (or inadequacy) of insulin receptors. On the other hand, autonomous, non-regulated insulin secretion is generally the cause of hypoglycemia. This condition is brought about by inhibition of gluconeogenesis, e.g. as a result of severe hepatic or renal failure, islet cell adenoma, or carcinoma. Hypoglycemia can, however, also be facilitated intentionally or unintentionally (factitious hypoglycemia).