This study aimed to investigate the impact of sub epidermal moisture (SEM) measurement and targeted pressure ulcer (PU) prevention, versus visual skin assessment and usual care, on mean SEM delta scores and early pressure ulcer development in acute hospital patients. A quantitative quasi-experimental observational approach was used. A total of 149 at risk acute hospital patients took part, 78 treatment, and 71 control. SEM deltas were recorded daily for a maximum of 5 days using the SEM Scanner (Bruin Biometrics LLC, Los Angeles, California), on three sites: the sacrum, the right heel, and the left heel, with enhanced and targeted PU prevention interventions occurring in those with an elevated SEM delta scores in the treatment group. Intention to treat analysis was used to guide the final composition of results. SEM PU represents PU development as identified by 2 days of sustained abnormal SEM delta scores, ≥0.5, after day one. The mean number of days completed by participants was just under 4 days, participants had many different comorbidities, with the most common being: hypertension, cancer, and chronic obstructive pulmonary disease. Results showed that following the introduction of SEM guided targeted treatments, participants in the treatment group yielded a statistically significant reduction in mean SEM delta scores (MD: 0.49; 95% CI: 0.59, 0.39; P < .0001), and in the odds of developing a SEM PU (OR: 0.59, 95% CI: 0.24 to 1.00; P = .05). In the treatment group, none of the participants developed a visual PU, whereas, in the control group, 1.41% (n = 1/71) developed a visual PU. Based on all the results, the following is concluded, (1). There was a greater reduction in mean SEM delta scores among those cared for using SEM measurement and targeted PU prevention, versus those cared for using visual skin assessment and usual care, and (2). the mean SEM delta scores was statistically significantly lower at the study end for those who received targeted treatments based on abnormal SEM scores. More research is now needed in other and larger at-risk groups to further validate what was found in this study.