Fungal Antigen in Serum (Quantitative)

This test measures markers in your blood, such as antibodies or antigens, that show whether your immune system is responding to a fungal infection. It can help identify fungi such as Histoplasma, Coccidioides, Blastomyces, or Aspergillus.

The test detects specific antigens produced by certain fungi in your bloodstream. These antigens are proteins that the body produces as part of the infection process. The test is used to identify infections caused by fungi like *Cryptococcus* or *Histoplasma*, among others.

Your doctor may order this test if you have symptoms that suggest a fungal infection, such as a lingering cough, fever, chest pain, night sweats, or unexplained fatigue. It may also be recommended if your immune system is weakened or if you live in or traveled to an area where certain fungi are common.

Your doctor may recommend this test if you have symptoms like fever, fatigue, or weight loss, or if you have a weakened immune system, certain medical conditions (like diabetes or HIV), or have recently undergone medical procedures that increase infection risk. It’s also used in monitoring people with known fungal infections.

This test is usually performed on a blood sample. A healthcare professional will clean your skin, wrap a band around your upper arm, and draw blood from a vein, most often in your elbow or hand. The procedure takes only a few minutes, and the sample is then sent to a laboratory for analysis.

A blood sample is drawn from a vein in your arm. The sample is then sent to a lab where it is analyzed using a sensitive immunoassay method to detect fungal antigens.

A negative result usually means no signs of a fungal infection were found, while a positive result suggests your body has responded to a fungus, either now or in the past. Some results may be borderline or unclear, so your doctor will interpret them alongside your symptoms, medical history, and other test findings.

Results can be positive (indicating fungal infection), negative (no detectable antigen), or inconclusive. A positive result suggests the presence of a fungal infection, but further testing may be needed to identify the specific fungus.