Diagnosing candidiasis. A new, cost-effective technique

To demonstrate the efficacy of normal saline as a culture medium for the rapid growth and detection of Candida.

During a six-month period in 1995, the authors examined 302 patients with vulvovaginal complaints. A wet smear diagnosis was accomplished in 271 patients; 31 had symptoms suggestive of a Candida infection, which was not confirmed by microscopy. Two patients were excluded, leaving 29 in the study group. Two samples of the vaginal discharge were collected from the vaginal fornices, with one sample placed in a tube of liquid Sabouraud medium and the second placed in a sterile, red-topped tube containing 5 mL of normal saline. Each saline culture was placed in a test tube rack and left to incubate at room temperature. The samples containing the Sabouraud medium were incubated in the hospital microbiology laboratory. Both samples were evaluated microscopically within 24-72 hours to detect the presence or absence of Candida organisms.

Of the 29 patients who had symptoms suggestive of Candida, 16 had a confirmed diagnosis of Candida employing both the saline method and Sabouraud medium. Eleven patients were negative for Candida with both the saline and Sabouraud; there was one false positive and one false negative in each group. The positive predictive value of the normal saline culture technique was 94.1%, with a negative predictive value of 91.7%. Sensitivity and specificity were 94.1% and 91.7%, respectively.

Using normal saline instead of Sabouraud's medium to culture Candida proved inexpensive, cost-effective and highly accurate for rapid diagnosis.