[florida2001]

is there a difference in a way how the blood is taken? which OGTT is the most accurate, the blood taken from vein or from the finger prick? just curious, because month ago they did venipuncture test 3 hr and the numbers were much lower then what I had on my glucometer in the same time of course.

 

[John.in.France]

Blood from your capillaries tends to be out of sync with blood from a vein (basically, the vein reflects the position about half an hour before hand).

That's why meters that allow you to use 'alternative sites' for testing usually suggest not using anything except the fingertip when checking for hypos.

In a stable situation, it possibly doesn't matter too much but you'll get some anomalous results if you compare a finger tip test with that from a vein. As always consistency is important.

 

[RCG]

They are two different things, and the answer hinges on what you mean by "accurate". In general, they are each "accurate" by their own standards. (if measured with a good instrument.)
If you are talking about what we measure with our meters, as opposed to a laboratory measurement, made with a calibrated instrument, the lab test is the more accurate.

In a venous sample, there is also the averaging effect of a large sample, whereas blood is not really homogeneous on a microliter scale.

 

[florida2001]

Hi, this is the difference in numbers taken with glucometer and blood taken from vein.


Glucometer results
Fast 82
30 min 175
60 min 170
90 min 150
120 min 145
150 min 120
180 min 63

Blood taken from vein
Fast 75
1 hour 127
2 hours 122
3 hours 44

 

[mbuster]

I think this shows the value of doctors using a CGM. I'd almost bet there was an undetected spike using hourly catches.