Blood Test Quickly Identifies Lethal Form of Sepsis

A new nanodiagnostic method using manual application of T2 magnetic resonance (T2MR) to detect Candida species was previously found to have high sensitivity and specificity with rapid time to result.

Candida is the most lethal form of common blood stream infections that cause sepsis, a potentially life-threatening illness in which the body has a severe, inflammatory response to a bacterial or fungal infection.

Scientists at Warren Alpert Medical School of Brown University (Providence, RI, USA) working with colleagues from several other institutions conducted a clinical trial from July 31, 2013, to April 24, 2014, at 12 centers. They collected blood specimens from 1,801 hospitalized patients between ages 18 and 95 years old who had a blood culture ordered for routine standard of care.

The teams used the T2Dx instrument that automatically completes all steps in the T2Candida panel after specimen loading. Specifically, T2Dx lyses the red blood cells, concentrates the pathogen cells and cellular debris, lyses the Candida cells by mechanical bead beating, amplifies Candida DNA using a thermostable polymerase (T2Biosystems, Inc.; Lexington, MA, USA) and pan-Candida primers for the intervening transcribed spacer 2 region within the Candida ribosomal DNA operon, and finally, detects amplified product by amplicon-induced agglomeration of supermagnetic particles and T2MR measurement.

The T2 Magnetic Resonance Assay, which includes the T2Candida and the T2Dx instrument, demonstrated an overall sensitivity of 91.1% and an overall specificity of 99.4%. The mean time to positive result for T2Candida was 4.4 hours, compared to 129 hours for blood culture and species identification. The mean time to negative result for T2Candida was 4.2 hours, compared to at least 120 hours for blood culture.

Eleftherios Mylonakis, MD, PhD, the lead author of the study said, “The ability to determine the presence or absence of Candida within hours compared to days is paradigm changing for patients at risk for these infections. It will allow us to move from a 'best-guess' approach in treating high-risk patients, such as cancer and transplant patients and patients in the Intensive Care Unit, to a more informed approach where we can quickly direct the best course of therapy potentially improving patient outcomes and saving lives.” The study was published on January 12, 2015, in the journal Clinical Infectious Diseases.

Related Links:
Warren Alpert Medical School
T2Biosystems, Inc.