The cost effectiveness of testing for onychomycosis versus empiric treatment of onychodystrophies with oral antifungal agents.

Onychomycosis is accurately diagnosed by potassium hydroxide preparations, fungal culture, or nail clippings for histologic examination. Onychodystrophy is often treated empirically as an onychomycosis with oral antifungal medications. Terbinafine, fluconazole, and itraconazole are effective, but costly, therapies for onychomycosis, which also require monitoring of blood values. We compared the cost effectiveness of confirming the diagnosis of onychomycosis before initiating treatment to administering empiric treatment of thickened nails with oral antifungal agents. Six hundred eighty-eight fingernails and toenails were submitted for diagnosis to our laboratory in 1997. We calculated the cost of treating all of those patients with oral antifungals as $590 per patient or $405,920 total. In contrast, the cost of testing all of those patients and treating only those with positive results was $296,360 total. We conclude that it is more cost effective to first confirm the diagnosis of onychomycosis and then treat only those with infection.