The ALT-70 Predictive Model Outperforms Thermal Imaging for the Diagnosis of Lower Extremity Cellulitis: A Prospective Evaluation

Publication date: Available online 10 July 2018

Source: Journal of the American Academy of Dermatology

Author(s): David G. Li, Anna K. Dewan, Fan Di Xia, Hasan Khosravi, Cara Joyce, Arash Mostaghimi

Abstract

Background

We previously demonstrated dermatology consultation to substantially reduce cellulitis misdiagnosis rates; however, broad implementation is impractical due to existing practice patterns and reimbursement systems. Meanwhile, efforts to improve diagnostic accuracy have culminated in point-of-care tools, including the ALT-70 predictive model for lower extremity cellulitis and thermal imaging.

Objective

To prospectively evaluate the performance of ALT-70 and thermal imaging in diagnosing lower extremity cellulitis in a head-to-head comparison.

Methods

We collected ALT-70 and thermal imaging data from patients with presumed lower extremity cellulitis and compared classification measures and accuracy for ALT-70, thermal imaging, and combination testing (ALT-70 plus thermal imaging).

Results

We enrolled 67 patients with ALT-70 and thermal imaging data. ALT-70 conferred the highest sensitivity (97.8%) and negative predictive value (90.9%), while combination testing had the highest specificity (71.4%) and positive predictive value (86.6%). ALT-70 had improved classification measures compared to thermal imaging. Combination testing conferred a marginal benefit to ALT-70 alone.

Limitations

Single-center design may limit generalizability.

Conclusion

ALT-70 outperformed thermal imaging in diagnosing lower extremity cellulitis. The accuracy of the ALT-70 was high and consistent with previously published reports. Broad implementation of ALT-70 into clinical practice may decrease misdiagnosis rates of lower extremity cellulitis.