Comparison of a semiautomated hand-held device to test minimal erythema dose before narrowband ultraviolet B phototherapy with the conventional method using matched doses.
BACKGROUND
A semiautomated hand-held device has been introduced in some phototherapy centres to establish the minimal erythema dose (MED) before treatment with narrowband ultraviolet (NBUV) B.


OBJECTIVE
To compare the semiautomated hand-held device with the conventional method of MED testing (a UV-opaque template and a panel of UVB fluorescent tubes), using the same series of incremented doses.


METHODS
Twenty-four patients referred for treatment with NBUVB phototherapy were included. Each patient had MED testing with the conventional method and the semiautomated hand-held device at the same level of the left and right back. The results were read by four investigators each time.


RESULTS
The semiautomated hand-held device was a significant estimator of the MED using the conventional panel method (P < 0.001; r = 0.97). The average ratio of the hand-held MED to the conventional MED was 67%. The mean difference between the methods was 165 mJ/cm(2) . The interobserver test showed very high agreement for both methods of MED testing (Cronbach α coefficient 0.97 for the hand-held MED tester vs. 0.93 for the conventional method).


CONCLUSIONS
The semiautomated hand-held device MED results were lower than that of the conventional panel method and may prolong the treatment course by 2-3 treatments. The hand-held tester is a fast and reproducible method, and may allow more phototherapy units, limited by staff and time, to do MED testing.
The Charles Centre, Department of Dermatology, St. Vincent's University Hospital, Dublin, Ireland.
M
M
Lynch
F
F
Carroll
A
A
Kavanagh
B
B
Honari
P
P
Collins
D000328:Adult; D000368:Aged; D001331:Automation; D004485:Eczema / Q000628:therapy; D004864:Equipment and Supplies; D004890:Erythema / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010789:Phototherapy / Q000009:adverse effects*; D011565:Psoriasis / Q000628:therapy; D014466:Ultraviolet Rays / Q000009:adverse effects*; D055815:Young Adult