New Blood Tests

New Whole Blood Test Quickly Identifies Sepsis Without A Culture

Sepsis kills over 250,000 people a year in America according to the Sepsis Alliance, a nationwide advocacy group committed to fighting sepsis throughout the country. Sepsis is responsible for more deaths than any cause except for cancer and heart disease. Tragically, clinicians often fail to notice the warning signs of sepsis when a patient is rapidly failing, or the results from a positive blood culture don’t arrive until it is too late to prescribe targeted antibiotics.

The challenge created by sepsis for clinicians and infectious disease personnel is immense. In addition to its huge fatality rate, it is also one of the most expensive conditions to treat, costing over $24 billion annually.1

Sepsis is a complex, life-threatening condition and researchers are pursuing various avenues to reduce patient deaths. In May of 2018 the FDA gave market clearance to a new test designed to rapidly identify the bacteria responsible for a patient’s septic infection, potentially allowing doctors to give more targeted antibiotics. The detector finds and identifies the extremely rare bacterial cells in blood samples, rather than having to culture bacteria in a lab dish, which can take days and substantially delay life-saving treatment. 2

One year after receiving market clearance from the FDA, T2 Biosystems, Inc.® announced on May 14, 2019 that “…results from a pivotal trial were published online in the Annals of Internal Medicine® journal. The study titled "Performance of the T2Bacterial Panel for Diagnosing Bloodstream Infections. A Diagnostic Accuracy Study," demonstrated decisive evidence for the first direct-from-blood, non-culture test cleared by the U.S. Food and Drug Administration (FDA) for the diagnosis of bloodstream infections by multiple bacteria.” 3

According to the company, at the present time, the T2Bacteria Panel is only FDA-cleared test to identify sepsis-causing bacteria directly from whole blood without having to wait for the results of a blood culture. This is a very significant breakthrough in the diagnosis and treatment of sepsis. A blood culture used to identify sepsis-causing bacteria takes from one to five or more days to get the results. All too frequently, this delay is too late to help treat a septic patient.

Regretfully, on a personal note, I’m all too familiar with the consequences of the delay caused by waiting on blood cultures to identify the sepsis-causing bacteria. Last fall I lost a good friend to a deadly sepsis infection. By the time his blood cultures were returned from the lab, he had already been dead for over a day. Had this new technology been available for my friend, perhaps he’d still be alive.

What happened to my friend is not at all uncommon. Prior to the development of the new technology in the T2Bacteria Panel, blood cultures were the primary method of diagnosing the sepsis-causing bacteria in a patient.

What makes this new technology so important for improved patient diagnosis and outcomes is that “The T2Bacteria Panel runs on the T2Dx Instrument and delivers results in three to five hours for the most common ESKAPE bacteria: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli.” 4

  1. Hong Nguyen, M.D., University of Pittsburgh Department of Medicine, and lead author of the study points out that “There are well known limitations with relying solely on blood cultures. Technology that can deliver pathogen results in a matter of hours from initial blood draw, a capability which is unlike any other FDA-cleared device in the market today, can allow clinicians to approach initial clinical BSI [blood stream infections] treatment in a more informed way.” 5

The multi-center study enrolled and collected blood specimens from 1,427 patients who had a blood culture ordered as part of the standard of care. In the pivotal trial, the T2Bacteria Panel and T2Dx Instrument demonstrated:

  • Blood cultures took between 32 and 111 hours to identify pathogens whereas the T2Bacteria Panel took 3.6 to 7.7 hours to do so.
  • In 78 percent of probable or possible BSIs, subjects had blood culture-negative/T2Bacteria positive results despite treatment with active antibiotics.
  • 24 hours after blood draw, 20 percent of patients with blood culture-positive/T2bacteria-positive results were still not receiving effective therapy.
  • The T2Bacteria Panel had a 99.7 percent negative predictive value.
  • The T2Bacteria Panel had overall sensitivity of 89.7 percent per subject and per assay.
  • The T2Bacteria Panel had overall specificity of 89.5 percent per subject and 97.8 percent per assay. 6

While this new technology represents a significant breakthrough in the fight against sepsis, it doesn’t solve a bigger problem. Most sepsis experts agree that many doctors, nurses, and family members don’t recognize sepsis until it is too late, delaying treatment until a life-threatening cascade of inflammation and organ failure has begun. 7

  1. Sepsis Alliance website https://www.sepsis.org
  2. Stat News, July 3, 2018
  3. May 14, 2019 07:00 ET | Globe Wire Press Release, Source: T2 Biosystems, Inc.
  4. Cite.
  5. Annals of Internal Medicine® online “Performance of the T2Bacteria Panel for Diagnosing Bloodstream Infections: A Diagnostic Accuracy Study” May 14, 2019
  6. Cite.
  7. Sepsis Alliance website https://www.sepsis.org