Fungal Culture Test

What is a fungal culture test?

A fungal culture test helps diagnose fungal infections. Fungal infections may happen if you are exposed to fungi (more than one fungus). Fungi are plant-like life forms, such as yeasts and molds. Fungi live everywhere:

• Outdoors in air, soil and on plants
• Indoors on surfaces and in the air
• On your skin and inside your body

Usually, if you are healthy, fungi will not make you sick. But many types of fungi can cause infections ranging from mild to life-threatening.

Fungal culture tests use different types of samples depending on the part of your body that's infected. Samples may include skin cells, blood, urine (pee), or other body fluid.

Your sample is sent to a lab and put in a dish with a special substance that helps grow any fungi in the sample. When there is enough material, it's checked under a microscope to see if it contains any fungi. Other tests may also be done to learn more about fungi in the sample.

Fungal infections may be grouped based on where they are in your body. In general, these groups include:

Superficial fungal infections. These infections affect the surfaces of your body, including your skin, genital area, and nails. They are very common and tend to be mild. But they often cause uncomfortable symptoms, such as itchy, scaly rashes. Two common superficial fungal infections are:

• Ringworm (tinea). It usually causes a ring-like rash on the skin. Ringworm on your feet is called athlete's foot, and on your groin, it's often called "jock itch." The fungus spreads from contact with infected people or animals. You can also get it from shared objects, such as towels, or surfaces, such as locker room floors.
• Yeast (candida). Yeast normally lives in and on your body. Usually, your immune system and certain "good bacteria" in your body keep it in control. If yeast grows out of control it can cause vaginal yeast infections and thrush, which affects your mouth or throat. This may happen if you have a weakened immune system or take certain medicines.

Deep and systemic fungal infections. These serious infections affect tissue deeper inside your body. The fungus may grow in your blood, lungs, and other organs, including your brain. If an infection affects many parts of your body at once, it's called a "systemic infection."

Anyone can get a deep fungal infection, but they are less common in healthy people. Most serious deep fungal infections happen in people who have weakened immune systems or are very sick with other conditions. Examples include:

• Aspergillosis. This infection is caused by breathing Aspergillus mold spores, which are commonly found in the air. It mostly affects your lungs but may also spread to other parts of your body. The spores usually don't cause illness in healthy people.
• Histoplasmosis. This lung infection is caused by breathing Histoplasma spores found in soil, usually where there are bird and bat droppings (poop). The infection can spread to other parts of your body, including your brain.
• Pneumocystis pneumonia. This lung infection spreads from person-to-person in the air. Healthy people may carry the fungus in their lungs without having symptoms.
• Invasive yeast infection (invasive candidiasis). This infection mostly happens only when your immune system is too weak to control the growth of yeast that's normally found in your body. It can affect your blood and organs.
• Sporotrichosis, or "rose gardener's disease." In the United States, this infection is caused by a fungus called Sporothrix schenckii. It lives in soil and on plants and gets into your skin through small cuts and scrapes. It usually causes infection under the skin, but it can also cause deep infections in your lungs and other organs.

What is it used for?

Fungal infections cause symptoms that can be a lot like bacterial and viral infections, but their treatment is different. So, a fungal culture test is used to:

• Find out if a fungus is causing an infection
• Help identify the type of fungus that's causing the infection
• Decide what treatment will work best
• Check to see if treatment for the infection is working

Your provider may also order a bacteria culture test at the same time as a fungal culture test.

Why do I need a fungal culture test?

Your provider is most likely to order a fungal culture test if you have symptoms that could be from a deep fungal infection. Your symptoms will depend on the type of fungus you may have and where it's growing. They may include:

• Cough, chest pain, or shortness of breath
• Fever
• Joint and muscle aches
• Headaches
• Chills
• Nausea and vomiting
• Fatigue
• Fast heartbeat

If you have symptoms of a superficial fungal infection on your skin or nails, your provider may be able to diagnose it with a physical exam and checking a sample under a microscope. But in certain cases, especially if your symptoms aren't getting better, you may need a fungal culture test.

Your symptoms will vary depending on the type of fungus you may have and where it's growing. They may include:

• Red rash
• Itchy, scaly, or cracked skin
• Hair loss
• Vaginal itching and/or discharge
• White patches inside the mouth
• Nails that are discolored (yellow, brown, or white), thick, or brittle

What happens during a fungal culture test?

To do a fungal culture test you will need to provide a sample of cells or fluid from the part of your body where a fungus may be growing. The most common samples are:

Skin scrapings or nail clippings

• Used to diagnose superficial skin or nail infections
• How it's done:
  • Your provider will use a special tool to take a small sample of your skin or nails. In certain cases, a skin biopsy may be needed.

Body fluids

• Used to diagnose yeast infections in your mouth or vagina. It may also be used to diagnose skin infections that have sores.
• How it's done:
  • Your provider will use a special swab to gather fluid and cells from your mouth, vagina, or an open skin sore.

Blood

• Used to find fungal infections in your blood.
• How it's done:
  • A health care professional will collect a blood sample. The sample is most often taken from a vein in your arm.

Urine

• Used mainly to find the cause of a urinary tract infection (UTI).
• How it's done:
  • You will collect a sterile sample of urine in a container, as instructed by your provider.

Sputum Culture

Sputum is a thick mucus that is coughed up from your lungs. It is different from spit or saliva.

• Used to help diagnose fungal infections in your lungs
• How it's done:
  • You may be asked to cough up sputum into a special container as instructed by your provider.

Many types of fungi grow slowly in the lab, so your test results may not be ready for days or weeks.

Will I need to do anything to prepare for the test?

You don't need any special preparations to test for a fungal infection.

Are there any risks to the test?

There is very little risk to having any of the fungal culture tests. If a sample of your skin is taken, you may have a little bleeding or soreness at the site. If you get a blood test, you may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

A positive test result means a fungus was found in your sample. You most likely have a fungal infection. Your test results will usually identify the specific type of fungus causing the infection.

Sometimes another test is done on your sample to help find out which type of medicine will kill the fungus or stop it from growing.

A negative test result means that no fungi were found in your sample. Something else is probably causing your infection.

If you have questions about your results, talk with your provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a fungal culture test?

If you are being treated for a fungal infection, be sure to take all your medicine as prescribed, even if you feel better. Many fungal infections clear up within a few days to weeks, but some infections require months or even years of treatment.