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SD Code Free Strips Batch no. S0318075.

bulkbiker said:
Well I'll try and use only one finger hole for 3 samples...i'll do Codefree, Caresens and Tee2 until the Caresens strips run out (about 25 left)..
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Good luck with that, I struggle to get enough of the red stuff for two tests!
 
Rachox said:
Good luck with that, I struggle to get enough of the red stuff for two tests!
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I struggle to get enough for 1 test! Is there any point at all in using the same drop of blood for more than one test? As far as my logic goes, there are trillions of red blood cells in a single drop of blood. Each of those will have a different amount of glucose in them. Same blood drop or different blood drops - to me it makes no difference at all.
 
bulkbiker said:
Well I'll try and use only one finger hole for 3 samples...i'll do Codefree, Caresens and Tee2 until the Caresens strips run out (about 25 left)..
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One problem with this test method that I have no handle on at the moment. is that when the pigsticker punctures the skin, then there are certain processes that kick off, Firstly the interstitial fluid near the surface of the skin comes out first, and gets reinforced by more recent capilliary blood from local supply tissues. Thus the first drop is slightly stale compared to blood that has been squeezed out, or in a second drop from the same site.

Then once the drop is on the surface awaiting application of the test strip, then it is oxidising and coagulating ever so slightly, thus changing composition.

Then the teststrip being a chemical conversion process will contaminate the drop of blood - this is minimised hopefully by the use of capilliary action so may not be a factor.

Then the body detects a wound has occurred, and rushes to repair the breach and repel invaders, thus changing the chemical composition around the test site.

These take time to affect the drop of blood, and may not be significant, but attempting three readings fom the same drop may be affected in time, so maybe rotate the order of test?
 
Bluetit1802 said:
I struggle to get enough for 1 test! Is there any point at all in using the same drop of blood for more than one test? As far as my logic goes, there are trillions of red blood cells in a single drop of blood. Each of those will have a different amount of glucose in them. Same blood drop or different blood drops - to me it makes no difference at all.
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Have you tried the TEE2 ? It requires significantly less blood than the SD Codefree that I used before.
 
Bluetit1802 said:
I struggle to get enough for 1 test! Is there any point at all in using the same drop of blood for more than one test? As far as my logic goes, there are trillions of red blood cells in a single drop of blood. Each of those will have a different amount of glucose in them. Same blood drop or different blood drops - to me it makes no difference at all.
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Blood glucose meters measure the glucose in the plasma rather than red blood cells - I am sure you knew that really:)
 
Mr_Pot said:
Blood glucose meters measure the glucose in the plasma rather than red blood cells - I am sure you knew that really:)
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To be quite technical, it is the interstitial fluid that it measures, Blood plasma as in the capilliaries and veins etc is different, which is why the lab measurement of venous blood as taken by the practice vampire does not tally with a fingerprick test taken at the same time. Meters used to be calibrated for whole blood readings so they matched the values on the YSI lab analyser which too is whole blood. Modern meters are now calibrated to what is termed 'Plasma' which is about 0.7 mmol/l lower. but it is still measuring the interstitial fluid between cells, not flowing blood.
 
Oldvatr said:
To be quite technical, it is the interstitial fluid that it measures, Blood plasma as in the capilliaries and veins etc is different, which is why the lab measurement of venous blood as taken by the practice vampire does not tally with a fingerprick test taken at the same time. Meters used to be calibrated for whole blood readings so they matched the values on the YSI lab analyser which too is whole blood. Modern meters are now calibrated to what is termed 'Plasma' which is about 0.7 mmol/l lower. but it is still measuring the interstitial fluid between cells, not flowing blood.
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I think you may be confusing measurement using a CGM with finger prick testing. A CGM measures glucose in interstitial fluid which is why there is a delay compared with a finger prick test which measures the blood in capillaries.
 
Bluetit1802 said:
According the manual for my modern meter, it is calibrated to measure whole blood.
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I think that is just a question of terms, the meter measures whole blood (no choice as that is what comes out of your finger), but is calibrated to display the plasma equivalent.
 
Bluetit1802 said:
According the manual for my modern meter, it is calibrated to measure whole blood.
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http://www.diabetesforecast.org/2013/jun/is-plasma-glucose-a-better-measure.html
https://www.joslin.org/info/plasma_glucose_meters_and_whole_blood_meters.html

They switched to plasma only a couple of years ago, Older meters and most Abbott meters were in whole blood, but do not meet the latest ISO tests 2015. This was a major reason why Abbott were excluded from the GMMMG review into bgl meters for NHS use. They were never even considered for inclusion, Only the Freestyle lite made the original stage 1 of the review. The SD is I believe a plasma calibration, as is the Caresense Dual that I use, but this does not explain why my SD reads 0,9 above the Caresense,
 
Oldvatr said:
http://www.diabetesforecast.org/2013/jun/is-plasma-glucose-a-better-measure.html
https://www.joslin.org/info/plasma_glucose_meters_and_whole_blood_meters.html

They switched to plasma only a couple of years ago, Older meters and most Abbott meters were in whole blood, but do not meet the latest ISO tests 2015. This was a major reason why Abbott were excluded from the GMMMG review into bgl meters for NHS use. They were never even considered for inclusion, Only the Freestyle lite made the original stage 1 of the review. The SD is I believe a plasma calibration, as is the Caresense Dual that I use, but this does not explain why my SD reads 0,9 above the Caresense,
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Yes, the Accu Chek (Roche) meter gives plasma readings. So are you and Mr. Pot saying that the HbA1c is plasma or whole blood?
 
Bluetit1802 said:
Yes, the Accu Chek (Roche) meter gives plasma readings. So are you and Mr. Pot saying that the HbA1c is plasma or whole blood?
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It is neither, it is the fraction of the separated out haemoglobin that has glucose attached.
 
Mr_Pot said:
I think you may be confusing measurement using a CGM with finger prick testing. A CGM measures glucose in interstitial fluid which is why there is a delay compared with a finger prick test which measures the blood in capillaries.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903977/
Whole blood is not the same as plasma blood. The article here assumes that the fingerprick penetrates to the dermis, and that all fluid expelled comes from the dermis. It ignores that the puncture open a channel through thr epidermis, and so will include interstitial fluid (IF) from there. In practice it depends on whether the lancet is set to 1 or 6 as to whether IF is dominant or not, I think that if you have to squeeze a drop out it is IF, and if it spurts out all over the floor then it is capilliary blood.
 
Oldvatr said:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903977/
Whole blood is not the same as plasma blood. The article here assumes that the fingerprick penetrates to the dermis, and that all fluid expelled comes from the dermis. It ignores that the puncture open a channel through thr epidermis, and so will include interstitial fluid (IF) from there. In practice it depends on whether the lancet is set to 1 or 6 as to whether IF is dominant or not, I think that if you have to squeeze a drop out it is IF, and if it spurts out all over the floor then it is capilliary blood.
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Bear in mind that blood is red and interstitial fluid is pale yellow. It is possible that blood could be diluted with interstitial fluid and some people wipe away the first drop and squeeze again, some people advocate not squeezing at all. I have never seen any instructions like that with a meter so I don't do either
 
When I was in hospital last year the nurse came to check my BS 2 or 3 times a day. She always squeezed. This is the only time anyone else has given me a finger prick.
 
Bluetit1802 said:
Yes, the Accu Chek (Roche) meter gives plasma readings. So are you and Mr. Pot saying that the HbA1c is plasma or whole blood?
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They use a YSI analyser so it is normally venous blood ( if drawn by nurse) or can be whole blood for capilliary extraction in hospital, Modern YSI equipment have an option to provide plasma equivalent Doctors and hospitals use whole blood values, home meters use plasma. I am not sure what the in site conversion software uses at all, The DVLA figures are Plasma equivalent I believe,

As regards Accuchek, they changed the strips so that there is an automatic seamless conversion for people using older meters. Other suppliers changed the meter calibration so requires replacing,
 
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