Diagnosis of Diabetes using HbA1c Pathway



Diabetes Diagnosis - HbA1c (information on diagnosis and local guidance)

Use of HbA1c in the role of diagnosis

  • HbA1c has been added to the diagnostic testing for patients who are at risk of diabetes. (WHO 2011)This test can be used instead of fasting glucose or OGTT.
  • It is not appropriate for every patient.
  • Patients do not need to fast for HbA1c; the test can be taken at any time:-
  • Therefore people with diabetes can be identified opportunistically.


HbA1c cannot be used in the diagnosis of:

  • All children and young people
  • Women who are pregnant or have been pregnant in the past two months
  • Suspected Type 1 diabetes, regardless of age
  • Sudden onset of symptoms of diabetes
  • Patients at high risk of diabetes who are acutely ill
  • Patients taking drugs that may cause a rapid rise in glucose i.e. corticosteroids or antipsychotic drugs (≤2 months). HbA1c can be used in patients taking these drugs longer term (>2 months) who are not clinically unwell
  • Patients with acute pancreatic damage or following pancreatic surgery
  • Patients with renal failure
  • Patients with HIV infection
  • Patients who have anaemia

Accurate diagnosis is essential to ensure the correct treatment pathway can be followed.

If there is a discrepancy between the HbA1c and the plasma glucose result with a strong clinical suspicion of diabetes,fasting plasma glucose should be the preferred test of choice and the HbA1c test can be repeated at 3 months.

Local Guidance

Diagnosis of diabetes requires fasting blood glucose or HbA1c.

  • Symptoms of diabetes include: weight loss, polyuria, polydipsia, lethargy, recurrent infections and blurred vision

Diagnosis confirmed:

Random glucose

Fasting glucose TWO required if NO symptoms

ONE required if symptoms

Oral Glucose Tolerance Test



Random HbA1c TWO required if NO symptoms

ONE result required if symptoms

≥ 11.1mmol/L

≥ 7.0mmol/L

≥ 7.0mmol/L

≥ 7.0mmol/L at zero hours or ≥ 11.1mmol/L at 2 hours



≥ 48mmol/mol

If HbA1c or fasting blood glucose level is raised but no symptoms of hyperglycaemia are present the test should be repeated in 2 weeks. If the level is still raised a diagnosis of diabetes is confirmed.

If the result is <48mmol/mol give lifestyle advice then repeat test in 6-12 months if the patient is asymptomatic, or before if patient develops symptoms.

Once a diagnosis is confirmed HbA1c can be used for monitoring 3 -12 monthly.

Altered Hyperglycaemia or Impaired Fasting Glycaemia (IFG) diagnosis:


  • Fasting glucose > 6.0 but < 7.0mmol/L or HbA1c 42-47mmol/mol.
  • These patients are at increased risk of diabetes and increased risk of cardiovascular disease. Review and re-check in 12 months.
  • Intensive lifestyle and risk management advice is a priority. HbA1c should be repeated annually.

GHNHSFT laboratories are unable to perform an HbA1c in a glucose specimen tube. This damages laboratory equipment.  Use Greiner Vacuette EDTA tube.

Dietary Therapies for the Management of Diabetes

The Community Dieticians Specialist Team (GCS) and Hospital Specialist Dieticians (GHNHSFT) have produced a joint position statement relating to Dietary Therapies for the management of Diabetes.

This guidance covers low carbohydrate diets and specialist weight management services currently offered in Gloucestershire. Please follow the resource link below to view.

Guidance on Patient Self-Monitoring of Blood Glucose and Prescribing of Blood Glucose Testing Strips

Guidance on Patient Self-Monitoring of Blood Glucose and Prescribing of Blood Glucose Testing Strips

This guidance aims to support people with diabetes and healthcare professionals involved in their care, to achieve optimal glycaemic control through the effective use of self-monitoring of blood glucose and Hba1c testing.

The following groups should be prescribed Gloucestershire formulary recommended blood glucose testing strips on the NHS and provided with meters:

  • Patients on insulin therapy or being considered for insulin therapy
  • Commercial lorry or bus drivers (DVLA Group 2 drivers)
  • Car and motorcycle drivers (DVLA Group 1 drivers) on medication which carries a risk of hypoglycaemia (e.g. sulphonylureas and glinides)
  • Women with diabetes who are either pregnant or considering pregnancy
  • Patients advised to test for other specific reasons by diabetes specialists

Blood glucose monitoring should also be considered temporarily where there may be periods of unstable glucose levels e.g. patients on weight loss programmes, especially those on sulphonylureas, during periods of illness or changes in therapy or during a course of steroid treatment.

In these cases patients should be informed at the outset that the monitoring is indicated for a limited period of time only. Testing strips should not be placed on repeat prescription for patients for whom blood glucose testing is only indicated on a temporary basis.

In all other groups there is limited evidence that either random or routine blood glucose monitoring is of clinical benefit.

Patients who wish to monitor their blood glucose more frequently than is clinically indicated will need to purchase their own strips.

Twice yearly HbA1c testing is recommended as a minimum by NICE.

Use of Blood Glucose Level Testing

Advice for patients using Hypoglycaemic Medications

The use of BGL testing is helpful for getting an instant guide of a person’s fasting glucose level. Since the advent of using HbA1c, the use of BGL has become less common but does have a role for certain situations. The majority of diabetics do not need BGL monitoring meters and are adequately maintained by use of HbA1c results. There are however certain circumstances in which it would be recommended that patients have access to BGL meters:

People using Insulin

This is the commonest requirement BGL monitoring, it gives the patient an immediate record of fasting glucose and hence an indication of the insulin dosage they should they should be giving themselves. The strips should be readily accessible for both T1DM/T2DM on insulin and any other insulin using patient.

People using Sulphonylureas

(SUs) who are car drivers: Since the DVLA have changed their recommendations regarding Class 2 licensing to recorded twice daily monitoring for the HGV driver population, it has been suggested that  Class 1 drivers should also have the ability to test (1). Although this is not a legal requirement it is recommended.  Therefore despite the evidence for the clinical benefit offered from this approach being limited, BGL meters should be provided to this cohort to give them the option to test before driving.

(SUs) who are not car drivers: As SUs can potentially cause hypoglycaemia, all patients on SUs should be considered for test strips with advice on appropriate frequency of use.

Changes in medication and the direct effect on BGL

This cohort of patients should be advised to use BGL for short times only, after changes in medication have occurred without waiting 2-3 months for an HbA1c. This empowers the patient and gives them confidence in the treatment plans.

People who have frequent or unexpected hypoglycaemic events

It is imperative that this group are given access to BGL meter strips. Hypoglycaemia events are potentially an avoidable situation that has physical and psychological consequences for people. Monitoring may allow reduction in the frequency of events but also potentially avoidable use of paramedics or hospital admissions.

Sick day rules

All people who have diabetes, whatever the underlying pathophysiology will become systemically unwell at some point in their journey. Those that have tendency to do this frequently may need to monitor their BGL closely. There is standardised guidance with regard to sick day rules, but the base line assessments are using BGL meters to advise further treatment.

People who have been advised by a diabetes specialist to test

This cohort of people may have ongoing issues with their diabetic control that needs monitoring closely by their Diabetes Specialist, or a range of other specific conditions necessitating testing e.g. renal patients, pancreatic transplant patients.

In summary, the use of BGL meters is variable throughout the county. We recommend that meters should only be given if there is good reason to do so. The results of BGL should be seen as a snapshot of the control but not as the long term trends that we should be using to help plan treatment regimen.



DVLA blood glucose monitoring requirements

  • Commercial lorry or bus drivers (DVLA Group 2) on insulin or sulfonylureas (eg. glibenclamide, glicazide) or glinides (eg. nateglinide, repaglinide) should regularly monitor blood glucose at least twice daily and at times relevant to driving.
  • DVLA Group 2 drivers on insulin should use a meter with a memory function capable of storing 3 months of readings.


  • DVLA requirements for car & motorcycle drivers (DVLA Group 1) diabetics managed by tablets which carry a risk of inducing hypoglycaemia (eg. sulphonylureas and glinides):
  • It may be appropriate to monitor blood glucose regularly and at times relevant to driving to enable the detection of hypoglycaemia.
  • For Group 1 entitlement the person must not have had more than one episode of hypoglycaemia requiring the assistance of another person within the preceding 12 months.
  • For DVLA Group 1 drivers who are not on oral medication at risk of hypoglycaemia or on insulin the need for blood glucose monitoring and frequency should be decided on an individual patient basis.


  1. Ref: www.gov.uk/current-medical-guidelines-dvla-guidance-for-professionals-conditions-d-to-f
Guideline for the management of Diabetes in frailty

The resource provides a guideline for the management of Diabetes in frailty. It includes the Rockwood Frailty Scale and also covers the following;

  • Assessment and degree of frailty
  • Recommended approaches to treatment
  • Blood sugar targets
  • Risk of hypoglycaemia
  • Choice of Insulin
  • Palliative care
Human versus Analogue Insulin in Type 2 Diabetes

Human versus Analogue Insulin in Type 2 Diabetes

The preferred basal insulin recommended by NICE is human NPH (Neutral Protamine Hagedorn) insulin. Long-acting insulin analogues are recommended by NICE only in specific patient circumstances (see below). However, for most people with type 2 diabetes, long-acting insulin analogues offer no significant clinical advantage over human NPH insulin and are much more expensive.

The following guidance has been produced as part of the national NHS QIPP programme to address the appropriate use insulin in type 2 diabetic patients.

Choose Human NPH insulin for type 2 diabetics requiring insulin

  • Initiation of insulin in these patients occurs after failure of appropriate oral or non-insulin injectable therapy.
  • The majority of patients will be obese with high blood glucose levels on waking which are similar throughout the day. If this is the case, patients should be started on night time (basal) human NPH insulin (Insuman® Basal, Humulin I® or Insulatard®)
  • If blood glucose levels rise throughout the day despite maximum oral therapy, or use of a basal insulin, then consider either:
    • Twice daily biphasic non-analogue insulin should be started (e.g. Insuman® Comb 25, Humulin M3®), OR
    • A basal bolus scheme (e.g. Insuman® Basal, Humulin I® or Insulatard® PLUS Insuman® Rapid or Humulin S® with meals) depending on patient’s preference.

Consider switching type 2 diabetics with poor control on analogue insulin to Human NPH insulin

For those patients already on analogue insulins whose control is poor (HbA1c persistently ≥ 69mmol/mol), switch to human insulins especially if on disposable regimen; see above for examples

Use analogue insulin in type 2 diabetic patients appropriately

Insulin analogues should only be considered in the following circumstances:

  • The patient is reliant on a professional to inject insulin, and use of a long-acting insulin analogue (insulin detemir, insulin glargine) would reduce the frequency of injections from twice to once daily
  • The person’s lifestyle is restricted by recurrent symptomatic hypoglycaemic
  • Patients who cannot use the device needed to inject human NPH insulin

When an insulin analogue is indicated, insulin glargine should be considered as the first choice, with detemir an option for any patients not well controlled on glargine.

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