What are the other Names for this Test? (Equivalent Terms)
- Calcofluor White Stain Tissue Tests
- Mycology Tissue Tests
- Potassium Hydroxide Preparation Tissue Tests
What is Tissue Fungal Infection Test? (Background Information)
- Tissue Fungal Infection Test is a common term for a variety of test methods to detect the presence of fungus in a tissue sample. These methods may include smear test and fungal culture
- Fungi (plural for fungus) are a diverse, complex group of microscopic organisms. A small subset may cause diseases that, in healthy individuals, are usually mild. However, those with weakened immune systems may experience severe illness. Over 50,000 different species of fungi exist in nature. Of these, less than 200 species can infect humans and only 50 commonly do so
- Fungi undergo a complex, two-phase life cycle. During their vegetative phase, fungi grow and develop. They then reproduce during their reproductive phase
- Yeasts are fungi that are single-celled and grow filaments during their reproductive phase. Molds are multi-celled and filamentous throughout their life cycles
- Many disease-causing fungi switch between yeast and mold forms depending on the temperature of their surroundings. At room temperature (25°C), they grow as multicellular molds. They then convert to single-celled yeasts when they enter a human host (body temperature at 37°C)
Fungal infections are called mycoses and they can infect different parts of the body. They fall into any of the 3 categories:
- Superficial mycoses of the skin and nails
- Subcutaneous mycoses beneath the skin
- Systemic mycoses involving multiple organs and organ systems
- Superficial and subcutaneous mycoses are fairly common. Examples include jock itch, ringworm, and athlete’s foot, which are caused by Trichophyton species. Other examples include genital infections caused by Candida species
- Systemic mycoses are most commonly observed in those with underdeveloped or weakened immune systems. These include individuals affected by HIV infection, undergoing cancer and immunosuppressant therapy, etc.
- Tissue Fungal Infection Tests are a series of tests to identify mycoses in bodily tissues. Different tests are performed depending on the type of mycosis
- Tests for superficial and subcutaneous mycoses include:
- Potassium hydroxide (KOH) prep: Microscopic observation of a sample for structures belonging to fungi
- Calcofluor stain: Dye that stains fungal structures
- Fungal culture: Tests for growth of a sample in media under fungi-specific conditions. This test yields slower results, but allows for susceptibility testing
- Tests for systemic mycoses include:
- Susceptibility tests: Applying various antifungal medications to a fungal culture to determine the most effective treatment for an individual’s mycosis
- Antigen tests: Identify various structures specific to fungi
- Antibody tests: Detection of specific antibodies created by the immune system upon exposure to fungi
- Genetic material tests: The use of PCR to detect traces of specific DNA and RNA that fungi are known to possess, but that which is absent in humans
What are the Clinical Indications for performing the Tissue Fungal Infection Test?
Following are the clinical indications for performing Tissue Fungal Infection Tests:
- Redness, itchiness, and burning on the skin, especially if ring-shaped
- White film on the tongue
- Vaginal itching, odor, or discharge
- Fever, chills
- Trouble breathing
- Severe headaches
- Stiff muscles and neck
How is the Specimen Collected for Tissue Fungal Infection Test?
Following is the specimen collection process for Tissue Fungal Infection Tests:
Sample required: Tissue from an area suspected to be infected or involved with fungal infection.
- Removing small amounts of tissue from the infected area in a sterile manner
- This can be done by scraping the tissue, biopsying the tissue using forceps, or biopsying the tissue using a needle
- Needle biopsy may either involve fine needle aspiration (FNA) or needle core biopsy depending on the location of the suspected infection
- No preparation is generally required for scraping the tissue
- However, needle biopsy may require special preparations, which shall be informed by the healthcare provider, depending on each individual’s specific circumstances and health condition
What is the Significance of the Tissue Fungal Infection Test Result?
A positive Tissue Fungal Infection Test may indicate a fungal infection. The species most commonly found in the tissue include:
- Actinomyces israelii
- Candida albicans
- P. brasiliensis
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- Evolutionarily, fungi are very closely related to humans. This makes fungal infections difficult to treat because the number of specific ways a drug can target a fungus, but not a human, is limited
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.