Abstract Objective Neuropsychological testing requires specific conditions of the clinician, client, and setting for valid standardized measurement and clinical interpretation, and yet only effort/symptom validity and orientation are routinely assessed in a standardized manner. Many other conditions are agreed to impact testing performance, including the developed construct of testing readiness: internal client states that are appropriate for undergoing neuropsychological testing (e.g., well rested, not intoxicated) as well as atypical conditions that require accommodations (e.g., mobility limitations, colorblindness). This study examined the preliminary validity of a testing readiness self-report screening measure developed to standardize the assessment and reporting of this aspect of profile validity. Method Community-dwelling young adults (N = 58) and older adults (N = 35) were screened for psychological and cognitive well-being, and then completed the Barnett-Coldiron Testing Readiness Inventory (BCTRI), followed by a short neuropsychological battery. Results The BCTRI displayed good internal consistency (α = 0.84) with a skewed distribution (−1.57) expected of healthy, testing-ready participant samples, and the only difference in BCTRI scores between participant demographic groups was found in psychological symptoms between age cohorts (t[57.99] = 2.27, p = 0.03). Additionally, the BCTRI showed discriminative validity with established neuropsychological tests – including an effort test (p = 0.81) – as well as concurrent validity with screening measures of overlapping psychological constructs (r = 0.60, p < 0.001). Conclusion The BCTRI displayed preliminary validity for the standardized assessment of testing readiness, as an aspect of client profile validity for neuropsychological testing, and the measure’s easy interpretation and quantitative reporting method show potential utility for both clinical and research settings. Future studies will investigate cutoff scores for clinical use.