Hello All
I have recently been diagnosed Type 2 and been prescribed Metformin 1000mg.
I am at a loss to understand the readings on my glucose monitor which shows a mmol/L number and my GP told me a HbA1c number.
I have found this to be very confusing. Can anyone explain these numbers to this dumbo please?
Regards
Scottwd
The fingerprick readings are measured in mmol/litre. The HbA1c readings are measured in mmol/mol. Even more confusingly, there are other measurements in use (mainly in the USA) which give readings in mg/dl and percentages. Interpret what you read on the internet with some care particularly where people do not quote what measurements they are using - many americans are totally unaware that there are other and more widely used systems.
Your fingerprick readings will generally vary quite a lot, depending mainly on the carbohydrate in the food you eat, but also because your liver will make glucose* and release it when it thinks you need it. This can be in response to many external stimuli - heat, cold, stress, illness etc. as well as hormonal influences. This all means that your fingerprick test is a snapshot of the moment, and (IMO) is best used to work out how well you can deal with various foods. It is however an unreliable guide to what your blood glucose is doing overall, which is why the HbA1c is used.
The HbA1c test counts the number of a particular type of red blood cell that has had a glucose molecule attached to it. As red blood cells live for about three months, this allows an estimate to be made (it's not an average!) of what your blood glucose has been doing overall for around the last three months - heavily skewed towards the most recent month.
Average blood glucose HbA1c for a non-diabetic population is around 38mmol/mol (graph attached). One standard deviation from that gives you an upper limit of 41mmol/mol, and "normal" blood glucose ends there. The UK pays GPs for detecting anyone with a BG of 48 mmol/mol or above, as that is the internationally agreed fallback figure that everyone agrees to be T2 diabetes. Unfortunately it's come to be assumed that you can't be diabetic unless your BG is above 48 - as I know only too well it's possible to have a raft of T2 symptoms at much lower (still abnormal) BG levels. Pre-diabetes had to be invented as a concept to cover the gap between the upper level of normal blood glucose and the 48 figure.
One of the problems is that a lot of the official targets for BG levels for T2 diabetics in the UK are abnormal BG levels. This is largely because the system assumes that T2 diabetes is progressive and that people will only get worse. There's a lot of evidence on this forum (have a look at the "Success Stories" forum) that shows very clearly that that approach is simply wrong - many of us have achieved normal BG levels, absence of symptoms, no medication etc by altering diet to cut back on the amount of carbohydrates eaten.
best of luck. Questions are free and encouraged. We've all been through it.
*Metformin works by interfering with your liver's ability to make glucose itself - metformin doesn't affect the glucose in what you eat.
[BTW, most of the technical detail in the above post is taken from Bilous and Donnelly's "
Handbook of Diabetes". ]
