Some older adults cannot meaningfully participate in the testing portion of a neuropsychological evaluation due to significant cognitive impairments. There are limited empirical data on this topic. Thus, the current study sought to provide an operational definition for a futile testing profile and examine cognitive severity status and cognitive screening scores as predictors of testing futility at both baseline and first follow-up evaluations. We analysed data from 9,263 older adults from the National Alzheimer’s Coordinating Center Uniform Data Set. Futile testing profiles occurred rarely at baseline (7.40%). There was a strong relationship between cognitive severity status and the prevalence of futile testing profiles, χ2(4) = 3559.77, p < .001. Over 90% of individuals with severe dementia were unable to participate meaningfully in testing. Severity range on the Montreal Cognitive Assessment (MoCA) also demonstrated a strong relationship with testing futility, χ2(3) = 3962.35, p < .001. The rate of futile testing profiles was similar at follow-up (7.90%). There was a strong association between baseline dementia severity and likelihood of demonstrating a futile testing profile at follow-up, χ2(4) = 1513.40, p < .001. Over 90% of individuals with severe dementia, who were initially able to participate meaningfully testing, no longer could at follow-up. Similarly, there was a strong relationship between baseline MoCA score band and likelihood of demonstrating a futile testing profile at follow-up, χ2(3) = 1627.37, p < .001. Results can help to guide decisions about optimizing use of limited neuropsychological assessment resources.