Apps that help patients assess their melanoma risk are not fail safe, a new study shows.

In fact, three of four apps incorrectly classified 30% or more of melanomas as unconcerning. The findings are published online in JAMA Dermatology.

Joel A. Wolf and colleagues at the University of Pittsburgh Medical Center tested the sensitivity, specificity, and positive and negative predictive values of four smartphone applications designed to assess melanoma risk. There were 188 images of lesions in the analysis. Each of which was evaluated by the four smartphone applications, and the test result was recorded as positive, negative or unevaluable. Of these lesions, 60 were melanoma and the remaining 128 were benign.

Sensitivity of the four applications tested ranged from 6.8% to 98.1%; specificity ranged from 30.4% to 93%; positive predictive value ranged from 33.3% to 42.1%; and negative predictive value ranged from 65.4% to 97%. The highest sensitivity for melanoma diagnosis was observed for an application that sends the image directly to a board-certified dermatologist for analysis, while the lowest sensitivity for melanoma diagnosis were applications that use automated algorithms to analyze images, the new study found.

The authors did not identify the apps included in the study by their commercial names because the study’s purpose was to determine the accuracy of such applications in general.

The authors suggest that reliance on these applications, which are not subject to regulatory oversight, and not seeking medical consultation can delay the diagnosis of melanoma and potentially harm users.

“Physicians must be aware of these applications because the use of medical applications seems to be increasing over time… the dermatologist should be aware of those relevant to our field to aid us in protecting and educating our patients,” they conclude.

Jae Jung, MD, PhD, a dermatologist at City of Hope Cancer Center in Duarte, Calif, calls the findings “very alarming.” He says it is risky business to rely on an app to say whether or not a mole is melanoma. “Currently, apps don’t have a place in detecting melanoma.”