Candida is a genus of fungus that can cause opportunistic infections in patients with compromised immune systems, and is rapidly becoming one of the main sources of nosocomial (hospital-acquired) infections. Candida test kits can obtain diagnosis, as well as help monitor treatment progress, either through a polymerase chain reaction (PCR), detecting beta-d glucen through the use of limulus amebocyte lysate (LAL), or through an enzyme-linked immunosorbent assay (elisa). Because fungal species like Candida Albicans are present as harmless gut or skin flora in most people with healthy immune systems, elisa tests offer an advantage in that they detect the interaction between fungal antigens and host antibodies, and so specifically reflect the presence of a truly dangerous infection.