Studies have shown that a substantial proportion of all people found to have diabetes had not been previously diagnosed.
It has been a consistent finding of population-based diabetes studies that a substantial proportion of all people found to have diabetes had not been previously diagnosed. Thus, diabetes surveys identify people with previously diagnosed, or known, diabetes (KDM), as well as those with newly diagnosed diabetes, whose diabetes is only found through blood tests undertaken in the survey.
The uncovering of new cases of diabetes when mass blood testing is undertaken is primarily because of the lack of symptoms associated with the early years of type 2 diabetes, meaning that those with diabetes may be unaware of their condition and therefore not seek medical attention for it. However, it should also be noted that since the clinical diagnosis of diabetes requires diagnostic blood glucose levels on two separate days, a proportion of those labelled as having undiagnosed diabetes in research studies may not in fact have diabetes if re-tested.
In any survey, the percentage of all people with diabetes, whose diabetes has been previously diagnosed, is often taken as a measure of how well the standard clinical services are managing to screen for and identify people with diabetes. A high percentage indicates successful screening, while a low number reflects an inability of medical services to screen for diabetes, and is often seen in developing countries where resources are limited.