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Home fasting blood glucose numbers much higher than arm - are arm tests accurate?

G

GreatGateway

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At my local nuffield hospital, I had a blood test where blood was drawn from my left mid arm. This was to give me a comparison value to measure my blood glucose against. At home, especially after warming up my hands to the point of them turning red, my fasting glucose is considerably higher. This has me scared as I don't know which results are the truth.

Arm: 5.1
Home: 6.9

How accurate are the arm blood tests?

Edit: Forgot to say I have Raynaud's. Will this affect my results from the arm as much as my hands?
 
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Blood glucose varies a lot during the day. Those tests weren't taken at the same time so they're not comparable. BG can go up after waking, even when still fasting.
Do you have trouble getting blood from your finger or why are you warming up your hands until they are red?
 

Yes, I have Raynauds so I have a lot of trouble drawing even a single drop of blood.
 
Antje77 said:
Have you looked intou alternative site testing? It's possible to get blood from other places than fingers, which may be very helpful with Raynaud's.
Click to expand...

I would need to discuss it with my GP first, which unfortunately leaves me a bit stuck. I need to get good evidence of my glucose while only permitted to get finger readings.
 
It is probably worth looking at the instructions with your meter.
Mine came with an alternative head for the pricking device and a manual which showed alternative sites.
You could at least try altentative sites if your BG monitor supports it.

How much do you know about BG testing?
Worth reading the forum for a while to get an idea of how it works and why each reading is likely to be different.

Edit: in answer to your original question, blood taken from the arm and tested by a laboratory is far more accurate than a home finger prick. Finger prick tests at a hospital are generally more accurate than home ones because they use more expensive and regularly calibrated equipment.

Out of interest why the Nuffield?
This sounds like a private consultation.
Have you been diagnosed with diabetes by your GP?
 
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The reality is, about the only way to roughly compare would be to sit in the phlebotomy room, allow your venous blood to be drawn, then immediately prick your finger, but even that will only be approximately the same.

Venous and capillary blood differ, in that it can take a while for blood to get from the veins to capillaries. Add in there anything that happens along the way, in terms of stress, eating, drinking, even water and all can influence what your meter returns.

I differ from you in that venous draws are alway higher than my finger prick testing, and even if I average it all out, my finger prick estimated A1c scores never, ever have matched lab levels.

After almost six and a half years, I accept this now, and view the two reading as different.

Having been living with diabetes, I now appreciate that's provided my finger prick scores are between x and y number, my A1c scores are likely to be good. I won't state those numbers as everyone is different in terms of their desirable zones. This is something you have to work out form yourself.

In saying that, I am not trying to be unhelpful, but for me to suggest you need to be between x or y could be completely wrong for you, and as such, unhelpful.

My advice to you would be to run a diary of blood glucose finger prick readings, alongside exactly what you have eaten, recording times alongside all of it, and also recorded how you felt.

Over a period, that will help you understand your own body.

If you need progress resorts for yourself, you can review your numbers for trends, and maybe where you see undesirably high numbers, but you could also do an interim A1c at 6-8 weeks to see the direction of travel of our your numbers.

There are a number of organisations offering A1c (and lots of other tests), which can be done at home, or in clinics, if your GP resists a short term test. Many do.
 

In my local situation, only nuffield could do Hba1c. Unfortunately I have an awful relationship with my GP, and no way to change them without paying even more through the nose at nuffield. A pharmacist was actually the first to teach me about how my ongoing symptoms could be diabetic in nature, and she advised I try to collect evidence ahead of seeing my GP so that the don't play the "It's all in your head" card again.
 

There are many commercial labs who can do HbA1c tests, and one NHS Lab which does a small number of tests, including the A1c in their lab during quieter hours, for a fee. Examples are:

https://medichecks.com/products/diabetes-hba1c-blood-test

https://bluehorizonbloodtests.co.uk/products/hba1c

https://monitormyhealth.org.uk/diabetes/

I have used Medichecks, and MonitorMyHealth for thyroid testing, and found both to be very good. I used Medichecks when I needed a wider panel of tests thank MMH could offer.
 

From this I must ask why you are convinced that it has to be a finger prick?
Alternative site testing is fully acceptable, and is sometimes the only option for long term T1s with pincushion fingers.

Assuming that your blood test at the Nuffield was a fasting BG and not an HbA1c then this looks normal and not diabetic. If it an HbA1c it is (if possible) even more normal and would rule out diabetes.

If you are concerted that you have diabetes but are struggling to produce enough evidence for a diagnosis I would recommend having an HbA1c at the Nuffield (or other testing organisation) because that is what would happen if you showed signs of diabetes from finger prick testing.

It was a long time ago but if I remember correctly, my diagnosis route was:
  • Sudden weight loss and weeing all the time
  • Finger prick test at Lloyds Pharmacy which was stratospheric
  • FBG test through the local GP which was also well high
  • HbA1c at local clinic organised by GP
  • "Got me bang to rights, Guvnor"
If you are having problems getting your GP to listen then a private HbA1c test should provide one of three things, hopefully. Definitely diabetic, definitely not diabetic, possibly pre-diabetic.

If you can afford it this then this should cut out a lot of uncertainty and worry.

Finally, again, there is no need to struggle to test through your finger tips.
If you test at an alternative site this will still be accurate enough to provide evidence (to yourself as well as others) about your BG control.

Can I point you towards these two pages, please?
https://www.diabetes.co.uk/Diabetes-diagnosis.html
which includes a reference to
https://www.diabetes.co.uk/fasting-plasma-glucose-test.html
Noting that according to the second reference your FBG from the arm of 5.1 mmol/l is well within the normal range and would not support a diagnosis of diabetes.
Your finger pricks of 6.9 mmol/l falls within the possible pre-diabetic range but is certainly nowhere near enough to support a diagnosis of diabetes. Further doubt is cast because of your difficulty in getting a blood sample from your finger and (with respect) your lack of understanding and experience of BG testing.
 
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