Certain populations of patients have more access to or higher use of diagnostic tests. Higher rates of testing will result in more diagnoses being made, which can make a diagnosis appear more prevalent in certain populations even if it is not.
For example, when comparing rates of hypercholesterolemia between an impoverished inner city population and a rich suburban population, a direct comparison of current diagnoses may not be fair because an imbalance in the rate of access to primary care could bias the rate of diagnosis.
Diagnostic access bias is a type of selection bias.
This post is part of a series of posts on bias in medical research. You can find the whole bias catalogue here.
You can find more evidence based medicine resources here.
Cite this article as: Justin Morgenstern, "Diagnostic access bias", First10EM blog, April 7, 2018. Available at: https://first10em.com/ebm/diagnostic-access-bias/.