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Diabetes care in Reading, Wokingham and West Berkshire

Diagnosis of T2DM, Fructosamine

New guidelines recommend the use of HbA1c measurement to diagnose Type 2 diabetes. Guidance is also given about the use and interpretation of Fructosamine.

HbA1c in diagnosis of type 2 Diabetes[i][ii], and the use of Fructosamine.

This guideline explains how to use how to use HbA1c in diagnosis and the use of fructosamine. As with all tests, there are some important variations which may need to be considered in some patient groups including those with renal failure, anaemia and heamoglobinopathy[iii]. HbA1c may over diagnose diabetes in some ethnic groups and the elderly, and this should be considered where HbA1c is modestly raised (<52 mmol/l)[iv].

 

HbA1c >47mmol/ on 2 occasions a month apart diagnose Type 2 diabetes. (if HbA1c is high then no need to do 2nd test)

 

When HbA1c 42–47 mmol/mol (6.0–6.4%)

•High risk of diabetes.

•Provide intensive lifestyle advice.

•Warn patients to report symptoms of diabetes.

•Monitor HbA1c annually.

 

When HbA1c under 42 mmol/mol (6.0%)

These patients may still have a high diabetes risk, Review the patient’s personal risk and treat as ‘high diabetes risk’, if clinically indicated.

 

When not to use HbA1c in diagnosis

 

•All children and young people.

•Pregnancy—current or recent (< 2 months).

•Suspected Type 1 diabetes, no matter what age

•Short duration of diabetes symptoms.

•Patients at high risk of diabetes who are acutely ill (HbA1c≥ 48 mmol/mol confirms pre-existing diabetes, but a value < 48 mmol/mol does not exclude it and such patients must be retested once the acute episode has resolved).

•Patients taking medication that may cause rapid glucose rise; for example, corticosteroids, antipsychotic drugs (2 months or less). HbA1c can be used in patients taking such medication long term (i.e. over 2 months) who are not clinically unwell.

•Acute pancreatic damage or pancreatic surgery.

•Renal failure.

•Human immunodeficiency virus (HIV) infection

 

Fructosamine

Fructosamine is an alternate method of assessing glycaemic control and may be useful in situations where A1C cannot be reliably measured. Fructosamines are compounds that result from glycation of some proteins, usually albumin, and measures changes in recent mean glucose over the preceding 10 days.

Fructosamine concentrations of people with well-controlled diabetes may overlap with those of people who are not diabetic, and thus is not useful as a screening test for diabetes. A 1 mmol mean rise in blood glucose with raise Fructosamine by 23 µmol. Falsely low fructosamine results may be seen with decreased blood total protein and/or albumin levels

Fructosamine use should be limited to monitoring glycaemic control with

  • Diabetic pregnancy
  • Haemoglobinopathy and some forms of anaemia.

Interpretation

There is no standard reference range available for this test, but as a guide:

Fructosamine (µmol)

HbA1c  “equivalent”

Interpretation

<260

<42

Normal

261-290

42-47

Diabetes risk or very well controlled DM

291-350

48-58

Target for glycaemic control in diabetes

351-490

59-85

Poor control of DM

>491

>85

Uncontrolled DM

Author Ian Gallen 2014-01-17



[i] Use of Haemoglobin A1c (HbA1c) in the Diagnosis of Diabetes Mellitus. The implementation of World Health Organisation (WHO) guidance 2011.

 

[ii] John et al, Use of HbA1c in the diagnosis of diabetes mellitus in the UK. The implementation of World Health Organization guidance 2011Diabetic Medicine 2013, 29, 1350–1357,

[iii] Anaemia and Abnormal haemoglobins may both produce lower HbA1c or with iron deficiency higher HbA1c

 

[iv] Ageing; older people without diabetes appear to have higher HbA1c values than younger individuals, being approximately 4 mmol/mol (0.4%) higher at 70 years than at 40. Ethnicity: Differences in HbA1c have also been consistently found between individuals from different races; with Afro-Caribbeans having values 4 mmol/mol (0.4%) higher than white Europeans with apparently the same glucose tolerance, A similar difference has been found between individuals of South Asian descent and white Europeans in the UK .

 

 

Download these guidelines here>