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Fasting BG/HBA1c which is most important

K

kashmere

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Hi I have been reading the boards for a few days following a few visits to the doctors. In February I had a really bad chest infection and as it had been over 12 months since my last visit the doctor did a routine MOT which discovered high blood pressure and elevated fasting level of 5.9. As that was slightly high she called for a repeat test and HBA1c as well as repeat kidney function to assess effect of the BP meds.

The second result came back at 5.8 for fasting but she seemed very puzzled that the HBA1C result was very low (didn't think to ask her the numbers sorry) and showed good control of my blood sugar. I am now awaiting an appointment for an OGTT but should I start taking action now to lower carbs or would that compromise the test results and give a false result?

Previous urine test was clear, cholestrol came back as very low (yet another puzzled look especially as I am very overweight), kidney function excellent, BP meds had reduced me almost to normal levels in three weeks. For both of the fasting tests I did have either the tail end of the chest infection and on the second one another cold/cough, seems the antibiotics have wrecked the immune system and its taking a while to get it back. Would this affect the readings?

I'm not sure how concerned I should be regarding the elevated FBG level and whether I should invest in a BG monitor to start checking whether there is a major problem or wait until after the OGTT for which there is a waiting list and I got the impression it could be 6-8 weeks before that happens.

I have never had any diabetes symptoms or anything I could vaguely connect to blood sugar problems. I do tend to eat a moderate carb diet as I am very overweight and have been losing steadily on this for the past year or so resulting in a 5 stone loss so far. Would this have masked any pre-diabetes/diabetes symptoms?

Any advice would be appreciated as obviously the doctor didn't give out too much information and I remember she got a bit testy when I asked pertinent questions about the BP meds as I'd previously worked with someone who had been prescribed ramipril and suffered several side effects. After the OGTT I'd like to go back with similar pertinent questions regarding the results.

Many thanks for reading
 
HbA1c - which depends on your BG levels over a few weeks - is far more telling that a single FBG score, which might have been influenced by other factors.

With a HbA1c of 5.8%, nothing bad is going to happen to you if you wait for a few weeks for your OGTT (many T2 diabetics work very hard to get into the 5% club). As you say, if you start low-carbing now, then by the time you get to the OGTT then you'll probably by very sensitive to carbs by the time you get to the test, possibly influencing the results for the worse.

A HbA1c of 5.8% is towards the top end of what some people consider "normal", so it might be that, whatever the results of the OGTT test, that you need to start thinking a bit more carefully about your diet. In which case a BG meter wouldn't be a bad investment (although there is a small chance that your Doc might give you one for free if you are diagnosed as a diabetic).

The bottom line is that only your doctor can diagnose you properly, so it's best to wait and see what (s)he says.
 
I understood your post to say you had a fg of 5.8-9
1)A fasting glucose of 5.8mmol/l is considered at the top end of normal in the UK and most of the rest of the world ; above 6mmol/l is considered to be impaired fasting glycaemia. In the US however levels above 5.6mmol/l are considered to be impaired fasting glycemia.
2) illness can raise blood glucose levels.
3) Your doc is probably looking at the whole picture and is concerned that you also have raised blood pressure and are overweight. This is in fact what the World Health Organisation suggests is the best thing to do rather than looking at a figure and saying below it you're OK and above it you're not. Giving you an OGTT will give her more information about how your body deals with a glucose load.
This link explains about IFG.
http://www.bupa.co.uk/individuals/healt ... -glycaemia
 
Thank you for your kind replies.

Yes it was the fasting reading at 5.8, the doctor didn't give me the result for the HbA1c she just said it was very low and showed good glucose control and asked if I'd been eating any different foods especially sweet stuff recently as if the two figures were totally out of sync with each other.

I wasn't worried about the FBG reading when I went for the test I was more concerned that the HbA1c would be off the scale as whilst I had the chest infection I was existing on fruit juices/smoothies, soup and bread as I had little appetite so expected it would be the longer term test that read higher.

Weirdly the doctor doesn't seem that bothered about the weight side of things just wants all the BP/BG numbers to be within the ranges in the guidelines it seems.

I shall keep on with my current eating plan, try and shed some more of the weight before the test and try not to worry about it too much.

Could I ask if a longer fasting period would cause a higher fasting result? They advise at my doctors not to eat/drink after 10 p.m except for water but my blood tests were at 9.15 a.m. and probably the latest I ate anything was around 7.30 the previous evening which is my normal routine apart from maybe a cup of tea at around 9 p.m.
 

It's always possible that if you fast for too long that your BG will drop too low and you'll experience compensatory a "liver dump". I'd just follow their instructions exactly and see what happens. Your quite lucky to be getting a GTT, most of us (T2s) just get diagnosed on the strength of a dodgy HbA1c.

You should try and push you HCP for the actual HbA1c number. Their definition of "normal" might not match ours.
 
"I wasn't worried about the FBG reading when I went for the test I was more concerned that the HbA1c would be off the scale as whilst I had the chest infection I was existing on fruit juices/smoothies, soup and bread as I had little appetite so expected it would be the longer term test that read higher."

I am not an expert as those posting above but you could not eat much more sugar and carbs if you planned it with the bread and fruit. So no doubt the fasting reading was high, and that would explain a low HbA1c if it was not your usual diet. You may be lucky and not have the dreaded D just a bad few days on the juice!!!
I would not worry until your results come through oh and by the way in my experience Drs etc tend to get ratty if you sound as if you know what you are talking about they like to feel slightly superior! I just say its my body and my disease and I would like to know the figures, but it does not endear you to them I am afraid.
 
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