The ALT-70 cellulitis model maintains predictive value at 24 and 48 hours after presentation

Background Cellulitis has many potential mimickers, and its misdiagnosis often leads to unnecessary hospitalizations and higher health care costs. The ALT-70 predictive model offers an objective tool to help differentiate between cellulitis and other clinically similar conditions at the time of initial emergency department (ED) presentation. Objective To evaluate the performance of the ALT-70 predictive model at 24 and 48 hours following ED presentation. Methods We performed a retrospective review of our prior cohort and expanded our data collection to include data at 24 and 48 hours after initial ED presentation. We compared classification measures for the ALT-70 at the time of initial ED presentation, 24 hours after presentation, and 48 hours after presentation. Results There was a statistically significant difference in median ALT-70 score between patients with true cellulitis and those with mimickers of cellulitis at all time points. Sensitivity, specificity, positive predictive value, and negative predictive value of the ALT-70 score was similar across all 3 time points. Limitations Single-center design may reduce generalizability. Conclusion At 24 and 48 hours, the ALT-70 performed similarly to the way it performed at the time of initial ED presentation, allowing for its use in a wider array of clinical settings.