|Background:||Glucose is stored in the body in the form of glycogen. Under hormonal control, glucose from either the diet or the body stores is mobilised and used as an energy source. The two hormones that are principally involved in glucose metabolism are insulin and glucagon. After feeding, the glucose levels in the blood increase, but then return to normal as insulin, secreted by the beta cells of the Islets of Langerhans in the pancreas, increase peripheral glucose utilisation and storage.
Glucagon is secreted by the alpha cells of the Islets of Langerhans in the pancreas in response to low glucose levels e.g during fasting. This homeostatic mechanism maintains the plasma glucose within relatively narrow limits. The main disease of this endocrine system is diabetes mellitus (DM), when either insulin is not secreted (Type I) or is secreted normally but the tissues are not respondent (Type II).
Random glucose estimations may be of value in the long-term control of a patient, but for diagnostic purposes a fasting glucose is of more use. It is sometimes necessary in the milder forms of the disease to perform a glucose tolerance test (GTT), in which the glucose levels are followed after ingestion of a standard dose of glucose.
Fasting: 2.2 – 6.0 mmol/L
Random: 2.5 – 11.0 mmol/L
Less than 2.78 mmol/24hours
Doctor will interpret CSF glucose level alongside serum/plasma glucose level.
|Specimen Requirements:||Sample type
|Turnaround Time:||2 hours|