Diagnostic access bias

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.