Glucose (plasma)

Alternative names, keywords

Samples required

Fluoride oxalate blood (grey cap, 2 mL tube). Smaller tubes are available for paediatric samples.

Fasting = over 8 hours with water only*

_{*Source:American Diabetes Association}

Test indications

Factors affecting test performance/ results

In very rare cases, gammopathy, in particular type IgM (Waldenström’s macroglobulinemia), may cause unreliable results.

Results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.

Reference range

Random plasma glucose

< 6.0 mmol/L.

If a random glucose is greater than 6.0 mmol/L a fasting glucose is recommended.

A random glucose ≥11.1 mmol/L is diagnostic of diabetes in a symptomatic patient.

Fasting plasma glucose (non-pregnant)

Cut-offs for the NHS Diabetes Prevention Programme (NHS DPP):

3.0 - 5.4 mmol/L	Normal.
5.5 - 6.9 mmol/L	Non-diabetic hyperglycaemia.
≥ 7.0 mmol/L	Diabetes if symptomatic. Repeat if asymptomatic.

_{Source: NHS Diabetes Prevention Programme, NICE PH38 ’Type 2 diabetes: prevention in people at high risk’}

The 2006 WHO classifications for fasting plasma glucose are:

3.2 - 6.0 mmol/L	Non-diabetic
6.1 - 7.0 mmol/L	Impaired fasting glucose
≥ 7.0 mmol/L	Diabetes

Fasting plasma glucose (pregnant)

Gestational diabetes is diagnosed by a fasting glucose 5.6 mmol/L or above.

_{Source: NICE NG3 February 2015}

Turnaround time

Same day (within 1h if urgent)

Enquiries

Biochemistry (Automation)

Test A-Z Index.