Syscan3, made by Rockeby Biomed, is another ELISA test for host antibodies (IgG) to Candida. It detects all clinically important Candidal types except C. krusei. It is supplied as 96-well microplates coated with purified Candidal antigen. The test has a turnaround time of 3 hours, with enzyme-linked readout achieved by an anti-IgG antibody. A trial has been conducted on invasive candidiasis. For immunocompetent hosts, positive predictive value was 62% and negative predictive value 84%. Perhaps because Syscan3 depends on the host immune response to create detectable antibodies, the test proved less sensitive for immunocompromised hosts, with a positive predictive value of 1.7%. It nevertheless demonstrated a negative predictive value of 93% in this sample. The results imply that Syscan 3 is relatively useful to rule out disseminated candidiasis.
PCR assays will soon be available for Candida and Aspergillus. And lest it seem difficult to select one of these new assays, the literature has already shown that a combination of assays can yield even better accuracy.