Diabetes, can the blood sugar value change depending on the finger used for blood sampling? – breaking latest news

My father (grand elder) has had diabetes mellitus for about 30 years. For five years he has been practicing basal (in the intervals between meals) and post-prandial insulin treatment. He measures his blood sugar with the glucometer three times a day, sometimes on two different fingers (at the same time, one after the other). The result is always different, sometimes even considerably (for example 170 in one finger and 140 in another). Can blood glucose vary by measurement site? The glucometer is dated, a significant amount of blood does not always come out, but the instrument does not give an error. What do you think?

He answers Stefano Pariniinternist, AUSL Ferrara, Association of Diabetologists (VAI AL FORUM)

I answer your interesting question referring to the document «Recommendations for blood glucose self-monitoring in diabetic patients» published in 2013 and still a reference today, the result of discussions between authoritative experts from the most important scientific societies dealing with diabetes (Amd, Sid, Siedp, Osdi, Sibioc, Simel). The data that the glucometer returns to us should not be considered “exact” like laboratory data, but by their nature “imprecise”within the scope and in line with the minimum analytical performance criteria declared in the ISO 15197 standard. In particular, a reflectometer should be considered adequate which in 95% of cases returns a value that can be ± 15 mg/dl per blood glucose below 100 mg/dl and ± 15% per blood glucose above 100 mg/dl, compared to the value we could have with an exact laboratory blood sugar. So a range – as in your case – of 30 points, with values ​​between 140 and 170 mg/dlis completely acceptable and indeed is increasing with higher values: for values ​​around 400 mg/dl, we should not be surprised by a much wider range, of 120 units between values ​​of 340 and 460 mg/dl. In conclusion, aware of its potential and its limitations, self-monitoring with a glucometer is and remains a valuable, irreplaceable and reliable tool.