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Prediabetes My A1C and fasting blood glucose don't line up?

C

CanadianGuy

Member
Messages
18
Location
canada
Type of diabetes
Other
Treatment type
Diet only
My Dr. showed me that my FBG in Jan 2017 was 6.0. He just showed me this in late October, and only after I asked (nobody told me...).

When I asked for another test, on Nov 10 2017... it came back higher, at 6.4. However, my A1c was 5.0 (which he said was perfect).

I do have a tremendous amount of anxiety lately, a huge phobia of needles and have been stressing very hard over the test results.

I don't have any symptoms that I am aware of (although I am a self-proclaimed hypochondriac).

I was able to go down more than 10 pounds (5'9" from 188ish to 175 currently) since October 31 2017. I was able to lose the weight with vigorous exercise, diet, and self-control.

However, I fear that my anxiety and anxiousness will spike my numbers.

My doctor doesn't have a whole lot to say other than lose weight and that i'm too young (31) to have such high numbers. Refuses to prescribe anxiety meds.

Any thought of a good A1c and a high FBG?
 
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Welcome to the forum, @CanadianGuy. Your HbA1c is firmly in the non-diabetic range, so you don't have anything to worry about. The higher fasting levels could be due to stress. Fasting levels of 6.0 and 6.4 are not hughly high, just a bit elevated.

Congrats on the weight loss and on improving your diet. Well done.

If you have any questions, just ask away. There are many very knowledgeable and helpful members on this forum.
 
Welcome to the forum, anxiety can definately raises levels and that is why your HBA1C being a 3 month average might be clearer in reflecting your health.

There seems to a be theme from my own experience and that of many posts on the forum, that fasting levels fall more slowly in response to lifestyle changes so that may explain why your fasting does not reflect you amazing HBA1C.
 
Hi @CanadianGuy and welcome to the forum. The HbA1c result shows the level of your blood sugars over the previous 8-12 weeks. It gives a better indication of your bs levels than the self testing you are doing in the morning. And it is clearly in the non diabetic range.
Your fbgs are just a snapshot of your bs level at the moment you take it. Meters aren't 100% accurate, and the figure can be influenced by various factors including stress, sleep, illness, or the 'Dawn Phenomenon' - where your liver dumps glucose into your bloodstream as you wake to give you a boost as you get going. DP is quite common even for non-diabetics.

Any fbg between 4-7 is good, don't worry yours are fine.
 
Thank you for your awesome replies! Prem51, the fasting test was from a lab at the same time as my A1c. So I am confused, because the lab said my FBG was 6.4 and my A1C was 5.0....
It seems weird to me and seems out of place, like how can my A1c be so low if my FBG is so high?
 
Your A1c is a long term measurement based on your blood glucose ALL the time.

Your fasting blood glucose is a measurement of just THAT moment. It is a morning test, and as @Prem51 points out, FBG can be affected by DP - all the processes in your body that are to do with you getting up and getting going!

My layperson's interpretation of your A1c of 5% is that it should not be any cause for such concern. It equates to a BG of 5.4 - see chart below.

 
Thank you very much. My doctor was giving me flak because in 2016 my FBG was 5.7, then 6.0 and now 6.4. But my A1c remains really good.
I don't seem to sleep really well and with this latest reading, I had extremely bad anxiety for 10 days leading up to the test, like a nervous wreck 80% of my waking hours and very poor sleep. Plus, when I get my blood drawn I get REALLY anxious.

My doctor basically ignored the A1c and said the FBG is used to diagnose and didn't even mention my 5.0 A1c until I asked.

So now I am super confused.
 
Think of prediabetes being an umbrella term for two different conditions, impaired fasting and impaire glucose tolerence. You can have one or the other or both. I have both but it started with just fasting problems.

While doctors in the UK focus on just HBA1C for diagnosis, like fasting tests, it does not reflect accurately for everyone. I was tested in 3 ways, fasting, HBA1C and glucose tolerence.

How would you feel about home testing your fasting blood glucose? It has been extreemly helpful for me to understand how stress, illness and lack of sleep affect me. Eating better and sleeping better has slowly reduced my fasting levels
 

Hi @CanadianGuy,

Anxiety can significantly impact your blood sugar levels.

This happens to me too. When I had my last appointment for labs, my fasting blood sugars were 4.3 just before entering the clinic (measured using my own glucometer). However, before taking bloods, the GP called me into his office to talk to me and I felt myself getting nervous. So, I measured my blood sugars right after leaving the clinic and they were 4.9. Evidently, there is nothing else to explain the rise apart from the anxiety. (By the way, the official test yieled fasting blood sugars of 4.6 -- so right in between.)

Maybe, you could get a glucometer and test your fasting blood sugars yourself to see what your morning levels are like when you are relaxed? This might help you to put your mind at ease.
 

My UK surgery no longer does fasting blood glucose tests, even on non-diabetics having routine health checks. They just do an HbA1c. Fasting BG tests might indicate a possibility of diabetes/pre-diabetes, but are no longer used for diagnosis without an HbA1c . They have to be followed up with an HbA1c, and unless that is sky high, a second HbA1c a week or two later. Sometimes an OGTT is used aswell as or instead of an HbA1c.

Any number of factors influence the fasting BG levels, such as anxiety, stress, disturbed sleep, rushing about at home then getting to the surgery, driving, waiting in the waiting room. They all affect it. You would do well, as suggested, to buy your own meter and start testing at home as soon as you get out of bed and wash your hands.
 
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