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Non-fasting blood tests are usually sufficient to monitor lipids
Although some GPs measure FBC, LFTs, B12 and folate there is not a good evidence base for doing this routinely. Rarely an unexpected drop in HbA1c will be due to anaemia. Liver transaminases (ALT or AST) should be measured prior to starting a statin, and again after 3 and 12 months. Long term monitoring of LFTs is not indicated.
In Type 2 Diabetes it is appropriate to measure TSH once at diagnosis, however annual TSH measurement is not recommended because the incidence of new hypothyroidism is low. (This differs from Type 1 Diabetes where annual testing is recommended).
Vitamin B12 levels may be reduced in patients on metformin. However the clinical significance is uncertain and we do not advocate screening for this.
This guidance does not cover other aspects of diabetes monitoring such as retinal screening and foot examination.
HbA1C: In symptomatic patients diagnosis of diabetes is based on one reading of greater than 48. In asymptomatic patients there needs to be 2 consecutive readings greater than 48 mmol/mol. If the second result is lower than 48 this value should be used in preference, the patient categorised as high risk and the HbA1c repeated in one year. For monitoring a minimum of 30 days for repeat testing is recommended.
For more detailed information see Exeter Diabetes Handbook
Every 6 months
Limitations of HbA1c
NICE guideline: Type 2 diabetes in adults: management. [NG28] Published December 2015
Lipid modification: cardiovascular risk assessment and the modification of blood lipids for the primary and secondary prevention of cardiovascular disease. NICE guideline [CG181] Published: July 2014.
NICE guideline: Chronic kidney disease in adults: assessment and management [CG182] Published July 2014.
This guideline has been signed off by the Pathology Optimisation Clinical Group on behalf of NEW Devon CCG.
Publication date: June 2017