NEW YORK (GenomeWeb) – The US Food and Drug Administration has cleared a molecular diagnostic test and instrument from T2 Biosystems for the detection of five yeast pathogens that cause bloodstream infections.
The T2Candida panel and the T2Dx Instrument are for the direct detection of Candida species in human whole blood specimens from patients with symptoms of invasive fungal infections or with conditions that predispose them to such infections.
The T2Candida panel detects Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata, and Candida krusei. The FDA said that the panel is the first direct blood test for detecting the five yeast pathogens.
According to the agency, traditional methods of detecting yeast pathogens in the bloodstream can take up to six days and identifying the specific type of yeast present in the bloodstream may take even longer. By comparison, the T2Candida panel and T2Dx Instrument can identify the five common yeast pathogens from a single blood specimen within three to five hours.
T2 Bio said that in a pivotal trial, its assay and instrument demonstrated a sensitivity of 91.1 percent and a specificity of 99.4 percent. The products are based on the Lexington, Mass.-based firm's T2MR technology, which uses superparamagnetic nanoparticles to measure the reaction of water molecules in the presence of magnetic fields. The reaction is commonly referred to as the T2 signal, and when a binding event occurs inside a sample, the T2 signal changes, making it possible to detect the presence of an analyte.
The FDA reviewed the T2Candida panel and T2Dx Instrument through its de novo classification process for devices with low- to moderate-risk that are first of a kind. The review was based on a clinical study of 1,500 patients in which T2Candida was nearly perfect in categorizing negative specimens as negative for the presence of yeast, the FDA said. In another clinical study of 300 blood samples with specific concentrations of yeast, the panel correctly identified the organism in 84 to 96 percent of the positive specimens.
"By testing one blood sample for five yeast pathogens — and getting results within a few hours — physicians can initiate appropriate anti-fungal treatment earlier, and potentially reduce patient illness and decrease the risk of dying from these infections," Alberto Gutierrez, director of the Office of In-Vitro Diagnostics and Radiological Health at the FDA's Center for Devices and Radiological Health, said in a statement.
The agency said that because false positives are possible with T2Candida, blood cultures should be performed to confirm results from the panel.