Sputum Koh Mount, in Visit Clinic

A KOH mount of sputum is a simple microscopic test where sputum is mixed with potassium hydroxide to dissolve mucus and host cells, clearing the specimen to reveal fungal elements (yeasts, budding cells, pseudohyphae, or branching hyphae). It helps detect fungal respiratory infections rapidly in the clinic or lab; negative or inconclusive results often need culture, special stains, or PCR for confirmation and species identification.

KOH mount is a simple microscopic test where skin, hair or nail scrapings are treated with potassium hydroxide to dissolve keratin and reveal fungal elements. It’s used to detect dermatophytes, Candida and Malassezia, offering rapid, inexpensive bedside diagnosis. Sensitivity depends on sampling and examiner skill; negative results don’t exclude infection, and culture or PCR may be needed for species identification.

A KOH test for the lungs is a potassium hydroxide preparation of respiratory samples (sputum, bronchoalveolar lavage, or tissue) examined microscopically to detect fungi. KOH dissolves mucus and cellular debris, revealing yeast, spores, or hyphae. It’s rapid and inexpensive but not highly sensitive; a positive result supports fungal lung infection, while negative results often require culture, antigen, or molecular testing for confirmation.

A positive KOH test usually indicates presence of fungal elements—yeast cells or hyphae—on a potassium hydroxide wet mount, supporting a diagnosis of candidiasis. In gynecology, a positive KOH "whiff" test (fishy odor when KOH is added) suggests bacterial vaginosis from anaerobic overgrowth. Clinicians interpret KOH results alongside microscopy, pH, and symptoms before treating.

KOH stands for potassium hydroxide. It is a strong alkaline compound (chemical formula KOH), also called caustic potash. In clinical labs a KOH mount is used to dissolve keratin and help identify fungal elements in skin, hair, or nail samples. KOH is caustic—handle with care, using appropriate protective equipment. It’s also used industrially in soap and chemical manufacturing.

The KOH mount detects fungal elements in skin, hair or nail samples. A positive result shows fungal hyphae or spores, indicating a superficial fungal infection (dermatophytes, Candida, Malassezia). A negative result means no visible fungi — suggesting a non‑fungal cause or that fungi were missed due to sampling, low organism load, or prior treatment. Further tests may be recommended if clinical suspicion remains.