Glucose (plasma)
Code:
GLUC (random), GLUCF (fasting)
Sample Type:
Plasma (Fluoride-oxalate: Grey Top)
Minimum volume: 1 mL
Paediatric minimum volume: 0.5 mL
Ref Ranges/Units:
Fasting:
3.0 – 6.0 mmol/L
6.1 – 6.9 mmol/L impaired glucose tolerance (‘pre-diabetic’)
>7.0 mmol/L suggestive of diabetes mellitus
Random:
3.0 – 7.7 mmol/L
7.8 – 11.0 mmol/L impaired glucose tolerance (‘pre-diabetic’)
>11.1 mmol/L suggestive of diabetes mellitus
Results <2.5 or >25 mmol/L (>15 mmol/L if under 16 years) will be phoned to the requesting clinician.
Turnaround:
Same Day (60 minutes from receipt for Urgent Samples).
Stability:
3 days at 15‑25°C
Special Precautions/Comments:
Fluoride-oxalate preservative is required to inhibit glycolysis and prevent falsely low results.
Additional Information:
Glucose is a carbohydrate which is the major product of digestion. Glucose is the main source of energy for cells (via glycolysis). Excess glucose is converted to glycogen for storage. Blood glucose levels are tightly controlled by several hormones, the most notable of which are insulin and glucagon. Plasma glucose can be measured on a fasting or random sample. A fasting sample is considered more reliable, but a random sample can be useful in an emergency setting.
Increased plasma glucose levels (hyperglycaemia) are most commonly seen in diabetes mellitus. This may be due to insulin deficiency (type 1 diabetes) or insulin resistance (type 2 diabetes). Rarer types of diabetes include Maturity of Onset Diabetes of the Young (MODY) and Latent Autoimmune Diabetes of Adults (LADA). Glucose may also be measured as part of an Oral Glucose Tolerance Test (OGTT) in the investigation of gestational diabetes. Other causes of hyperglycaemia can include severe stress, pancreatitis and thyroid dysfunction.
Low plasma glucose levels (hypoglycaemia) are less common but can be seen in fasting hypoglycaemia, reactive hypoglycaemia, and insulin-induced hypoglycaemia. Rarer causes of hypoglycaemia may include an insulin-secreting tumour (insulinoma) or hypopituitarism.
South of Tyne & Wear Pathology Centre
