From the Research
Yes, a mouth swab can miss an oral fungal infection. According to the most recent and highest quality study 1, oral fungal infections are opportunistic and due to impaired host resistance, and deep fungal infections can clinically mimic other pathologic conditions. The study highlights the importance of proper diagnosis and management of oral fungal infections. Swab tests for oral fungal infections like candidiasis (thrush) have limitations in sensitivity, meaning they may not always detect fungal organisms even when present. False negatives can occur due to sampling error, inadequate specimen collection, prior antifungal medication use, or if the infection is located in an area not reached by the swab.
Key Points to Consider
- The reliability of swab tests depends on proper collection technique, which requires swabbing the affected areas thoroughly 2.
- For more accurate diagnosis, healthcare providers often combine clinical examination with laboratory testing, including oral rinse cultures, tissue biopsy, or direct microscopic examination 3, 4, 5.
- If a fungal infection is suspected despite a negative swab result, additional diagnostic methods may be necessary to confirm the diagnosis.
- Healthcare providers often rely on visual examination of characteristic white patches or lesions when diagnosing conditions like oral thrush, even if laboratory confirmation is pending 1.
Diagnostic Approaches
- Clinical examination is fundamental in diagnosing oral candidiasis, and microbiological techniques are used to confirm the diagnosis or establish a differential diagnosis with other diseases 2.
- Staining (10% KOH) and culture (Sabouraud dextrose agar) are commonly used methods for diagnosing primary candidiasis, and identification of individual species of Candida is usually carried out with CHROMagar Candida® 2.