Microscopic diagnosis of vulvovaginal candidiasis in stained vaginal smears by Dutch general practitioners

To determine the accuracy of the microscopic diagnosis of vulvovaginal candidiasis (presence of [pseudo] hyphae and blastospores) in stained vaginal smears in clinical practice.

General practitioners trained in diagnosing vulvovaginal candidiasis performed microscopy of 324 stained vaginal smears. These smears were sent to the pathologist for confirmation of the microscopic diagnosis of the clinician; cytologic diagnosis by the pathologist was considered the gold standard.

In 104 of the 342 cases Candida was established by the pathologist. The clinicians made 24 false positive and 50 false negative diagnoses of Candida. Sensitivity and specificity of the microscopic diagnoses of the clinicians were 52% and 89%, respectively. The most frequent reason for a false positive diagnosis was presence of hairs, whereas the most frequent reason for a false negative diagnosis was understaining of the smear.

This study shows that even in stained smears it is difficult for clinicians to recognize blastospores and (pseudo)hyphae. Efforts are clearly needed to improve the quality of the clinical diagnosis of vulvovaginal candidiasis.