The Sensitivity and Specificity of Potassium Hydroxide Smear and Fungal Culture Relative to Clinical Assessment in the Evaluation of Tinea Pedis: A Pooled Analysis

Abstract

Background. There are relatively few studies published examining the sensitivity and specificity of potassium hydroxide (KOH) smear and fungal culture examination of tinea pedis. Objective. To evaluate the sensitivity and specificity of KOH smear and fungal culture for diagnosing tinea pedis. Methods. A pooled analysis of data from five similarly conducted bioequivalence trials for antifungal drugs was performed. Data from 460 patients enrolled in the vehicle arms of these studies with clinical diagnosis of tinea pedis supported by positive fungal culture were analyzed 6 weeks after initiation of the study to determine the sensitivity and specificity of KOH smear and fungal culture. Results. Using clinical assessment as the gold standard, the sensitivities for KOH smear and culture were 73.3% (95% CI: 66.3 to 79.5%) and 41.7% (34.6 to 49.1%), respectively. The respective specificities for culture and KOH smear were 77.7% (72.2 to 82.5%) and 42.5% (36.6 to 48.6%). Conclusion. KOH smear and fungal culture are complementary diagnostic tests for tinea pedis, with the former being the more sensitive test of the two, and the latter being more specific.

Studying the clinic mycological pattern of the dermatophytic infection attending OPD in tertiary care hospital in eastern Uttar Pradesh and Bihar

“…Similar results were found in other studies. [27][28][29][30] In studies conducted between 2002 to 2011, T. rubrum was the most common isolate while in some studies T. mentagrophytes was seen as most common isolate. Similar findings were also observed by Sahai and Mishra and Bhatia and Sharma.…”

Global perspectives for the management of onychomycosis

“…KOH is a direct technique involving degraded keratin and allows visual inspection of the fungal structures . KOH is a sensitive diagnostic test, whereas culture is more specific (Table ) . Culture allows for the isolation of the causal agent, species differentiation, and evidence of viability .…”

Diagnosis of tinea pedis by the Dermatophyte Test Strip

“…1 However, it is difficult to diagnose tinea pedis visually because there are many similar diseases. 2,3 Thus, a definitive diagnosis by mycological examination is necessary before the initiation of treatment for tinea pedis. 2,3 Direct microscopy and fungal culture are used as test methods.…”

“…2,3 Thus, a definitive diagnosis by mycological examination is necessary before the initiation of treatment for tinea pedis. 2,3 Direct microscopy and fungal culture are used as test methods. [2][3][4] However, direct microscopy has the disadvantage that the detection sensitivity is affected by the skill of the person who performs the test, 4 while fungal culture takes 2-3 weeks for the identification of pathogenic fungi and has a low identification rate.…”