Galactomannan is a polysaccharide antigen found in the cell walls of some fungi, notably Aspergillus species. Testing for galactomannan in serum is a diagnostic tool used to aid in the diagnosis of invasive aspergillosis, a serious fungal infection that primarily affects immunocompromised individuals.
Serum galactomannan testing involves collecting a blood sample from the patient and then performing an enzyme immunoassay (EIA) to detect the presence of galactomannan antigen. The test has been shown to have variable sensitivity and specificity depending on factors such as the patient population, the timing of specimen collection, and the presence of interfering substances.
Elevated levels of galactomannan in serum may indicate the presence of invasive aspergillosis, but it is important to interpret the results in conjunction with clinical findings, imaging studies, and other diagnostic tests for a comprehensive assessment.
Galactomannan testing in serum is most commonly used in immunocompromised patients, such as those with hematologic malignancies, recipients of hematopoietic stem cell transplants, and solid organ transplant recipients, who are at increased risk of fungal infections. It can aid in early diagnosis and initiation of appropriate antifungal therapy, potentially improving patient outcomes.