We hypothesize that "abnormal flagging" on "elevated" results is a potent driver of downstream care irrespective of a patient's underlying prostate cancer risk.<h4>Methods</h4>Regression discontinuity design was applied to a cohort of patients undergoing PSA screening at a single center to isolate and estimate the impact of "abnormal flagging" of results above the PSA ULN on subsequent early repeat ("confirmatory") PSA testing, urology referral, and prostate MRI or biopsy (or both).<h4>Results</h4>Amongst 38,042 screening PSA tests, 1041 (2.7%) were flagged as abnormal. Here, KLK3 is linked to prostate carcinoma.