Table 1.

Factors that affect the detection rate of KOH smear

1A) Sensitivity, specificity, PPV and NPV of KOH smear
Dermatologist’s clinical suspicion of cutaneous fungal infection			Dermatologist’s eventual diagnosis of cutaneous fungal infection after KOH smear result available (N)						Total
			Negative		Positive		Uncertain
High	KOH smear result	Negative	15		65		0		80
		Positive	0		149		0		149
		Total	15		214		0		229
Medium	KOH smear result	Negative	50		0		1		51
		Positive	0		29		0		29
		Total	50		29		1		80
Low	KOH smear result	Negative	48		1		1		50
		Positive	0		14		0		14
		Total	48		15		1		64
Total	KOH smear result	Negative	113		66		2		181
		Positive	0		192		0		192
		Total	113		258		2		373
Overall sensitivity of KOH smear: 0.74
Overall specificity of KOH smear: 1
Overall PPV of KOH smear: 1
Overall NPV of KOH smear: 0.62
NPV of KOH smear in high suspicion group: 0.19
NPV of KOH smear in medium suspicion group: 0.98
NPV of KOH smear in low suspicion group: 0.96
1B) Logistic regression to evaluate the relationship between the individual variables and the probability of a positive KOH smear result in those who had an eventual diagnosis of cutaneous fungal infection
Variable				P		Odds ratio (OR)		95% confidence interval (CI) for OR
								Lower		Upper
Skin sampled by dermatologically-trained personnel (yes)				0.001		3.03		1.58		5.81
Topical steroids used before skin sampling (yes)				0.12		0.54		0.25		1.17
Topical antifungals used before skin sampling (yes)				0.24		0.67		0.35		1.30
Systemic antifungal used before skin sampling (yes)				0.015		0.19		0.05		0.73