Response to an audit of oral glucose tolerance testing

Dear Sir,

The recent article by Ryan et al ¹ is commendable. It is interesting to note that oral glucose tolerance testing (OGTT) is recommended for the diagnosis of diabetes mellitus according to the Diabetes Australia and NHMRC guidelines where fasting or random blood glucose concentration is not diagnostic of diabetes mellitus. ²

In India OGTTs are used variably, often being combined with fasting and postprandial plasma glucose results, as well as with estimations of glycated haemoglobin (HbA1c). American Diabetes Association guidelines are generally recommended for practice in India, with local variations in policies. No major literature of a large-scale audit by a clinical biochemistry laboratory is available. This study provides a framework on which OGTT audits can be conducted.

However, a few additional pieces of information might have been beneficial:

The laboratory electronic database was searched to extract the number of OGTTs requested. ¹ However, screening of patient records from the outpatient department units who handle such patients could have revealed the number of patients in whom OGTT was indicated but not requested;

A major factor affecting OGTT is its reproducibility. A wide variety of preanalytical factors including patient preparation, type of glucose administered and factors associated with the test itself are responsible. ³ It would have been interesting to audit who takes responsibility for the correct supervision of the test?

Was the policy to repeat fasting glucose measurement after one year in type 2 diabetes mellitus and then follow up with OGTT if indicated (as per Diabetes Australia and NHMRC guidelines ² ), reviewed? (This study was for one and a half years);

Clinical biochemistry laboratories are now focusing on ‘outcomes research’, which is believed to bring out the ‘worth’ of the laboratory in patient management. With this in mind, it is worthwhile to highlight the first action taken by the physicians in terms of diet, counselling, drugs or other management.

DECLARATIONS

Competing interests: None.

Guarantor: SC.