Multidomain geriatric assessment batteries are increasingly integrated into digital health platforms for older adults monitoring, yet their internal consistency and cross-domain behavior under real-world conditions remain insufficiently examined. This study presents a correlation-based evaluation of a multidomain geriatric assessment dataset collected at two time points from 616 community-dwelling older adults (i.e., above 65 years old) in Greece. Pairwise Pearson correlation analysis examined test-retest stability, construct-level associations, and cross-domain coherence across balance, frailty, mental health, sleep quality, quality of life, and lifestyle measures. Strong correlations (r > 0.9) were observed for test-retest measurements, anthropometric clusters, and frailty-balance-fear constructs, while moderate correlations (0.4 < r < 0.7) reproduced known relationships between depression, sleep quality, functional independence, and quality of life. Composite multidomain screening subscores exhibited weak internal coherence and limited test-retest stability, highlighting implementation-sensitive limitations. These findings support correlation analysis as a transparent validation step prior to integrating geriatric assessment batteries into digital health and decision-support platforms.