This study evaluates whether expressing minimal erythema dose (MED) reference ranges in Standard Erythema Dose (SED) units reduces variability caused by differing ultraviolet wavelengths in phototesting. Analysis of two non-photosensitive population datasets demonstrated that converting MED from mJ/cm² to SED substantially compresses inter-waveband variation, producing reference ranges closely aligned with the original SED-defining study. These findings support the use of SED-based reference ranges to improve consistency across photodiagnostic services, while emphasising the continued value of establishing local ranges tailored to specific equipment and populations.
EADIE et al. (Sat,) studied this question.