A spot test for detection of cobalt release - early experience and findings.

It is often difficult to establish clinical relevance of metal exposure in cobalt-allergic patients. Dermatologists and patients may incorrectly assume that many metallic items release cobalt at levels that may cause cobalt dermatitis. Cobalt-allergic patients may be unaware that they are exposed to cobalt from handling work items, causing hand dermatitis. To present early findings with a newly developed cobalt spot test. A cobalt spot test based on disodium-1-nitroso-2-naphthol-3,6-disulfonate was able to identify cobalt release at 8.3 ppm. The test may also be used as a gel test if combined with an agar preparation. We found no false-positive reactions when testing metals and alloys known not to contain cobalt. However, one cobalt-containing alloy, which elicited cobalt dermatitis in cobalt-allergic patients, was negative upon cobalt gel testing. The cobalt test detects amounts of cobalt release that approximate the elicitation concentration seen in cobalt-allergic patients. It may serve as a useful tool in dermatology offices and workplaces.