Use of HbA1c in the role of diagnosis
HbA1c cannot be used in the diagnosis of:
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.
Diagnosis of diabetes requires fasting blood glucose or HbA1c.
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
≥ 7.0mmol/L at zero hours or ≥ 11.1mmol/L at 2 hours
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:
GHNHSFT laboratories are unable to perform an HbA1c in a glucose specimen tube. This damages laboratory equipment. Use Greiner Vacuette EDTA tube.
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
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:
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 regimes.
DVLA blood glucose monitoring requirements
The resource provides a guideline for the management of Diabetes in frailty. It includes the Rockwood Frailty Scale and also covers the following;
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
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 regimes; see above for examples
Use analogue insulin in type 2 diabetic patients appropriately
Insulin analogues should only be considered in the following circumstances:
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.