At the Association for Molecular Pathology annual meeting and exposition this week, Immunexpress launched a rapid molecular diagnostic test that could enable ruling in or ruling out sepsis in one hour.
The SeptiCyte Rapid test is different from almost all other sepsis tests on the market by means of its operation directly from a blood draw, Immunexpress CEO Rollie Carlson told LabPulse on the sidelines at AMP in Phoenix.
Testing directly from a blood draw shaves a day or more off the time to diagnose whether a patient has sepsis or a bacterial or viral infection, he said, adding that a fast diagnosis is especially important for sepsis, with the mortality rate for an infected patient rising rapidly as each hour passes.
“The test is designed for the early detection of sepsis [because] late-stage sepsis is actually quite easy to detect,” Carlson said. “When a physician is suspicious that a patient has sepsis … [he or she] would typically be thinking about a blood draw at that time,” and the handheld test can be run using the blood draw.
The Seattle and Brisbane, Australia-based firm obtained U.S. Food and Drug Administration (FDA) 510(k) clearance for its SeptiCyte Rapid test last year, running on the sample-to-answer Biocartis Idylla molecular testing platform. The FDA greenlighted the test as an aid in differentiating sepsis from infection-negative systemic inflammation in hospitalized patients suspected of sepsis. Immunexpress has also obtained the CE Mark for SeptiCyte Rapid, enabling its use in the EU and other regions that accept the designation.
SeptiCyte Rapid uses PCR to detect mRNA signatures in blood and evaluate the host response to systemic infection. As such, it differs from tests on the market that measure protein markers such as C-reactive protein and procalcitonin, or that detect the presence of molecular markers that are indicative of the presence of a sepsis infection.
According to Immunexpress, its test has a high negative predictive value and high positive predictive value in differentiating sepsis from systemic inflammatory response syndrome (SIRS), which presents as inflammation throughout the whole body.
SIRS may be caused by a severe bacterial infection such as those associated with sepsis, or by trauma or pancreatitis, according to the National Cancer Institute.
Carlson said SeptiCyte Rapid addresses the urgent need for rapid and sensitive diagnostic testing at the point of care that provides physicians with the information needed to rule out sepsis with high confidence or expedite preventative action with prompt therapeutic interventions.
The test is fully automated from sample to result, with all reagents integrated within a single-use cartridge and requiring only two minutes of hands-on operation. It interprets results using four probability bands, correlating its SeptiScore with sepsis risk.
“If you have the highest probability of sepsis, you really want to be able to administer antibiotics immediately and be able to treat [the condition],” Carlson said. “Our test also has a rule-out [feature]. If it's a low probability of sepsis, then most likely you should be looking at other etiologies.”
Numerous companies have entered the market in recent years to develop and commercialize assays that help clinicians diagnose sepsis by ordering tests from laboratories. Among the companies, Lexington, MA-based T2 Biosystems provides FDA-cleared molecular tests for the detection of sepsis directly from blood and without a blood culture. T2’s test, which is not a host response assay, detects molecular markers of bacterial and fungal infection.
Burlingame, CA-based Inflammatix, on the other hand, is developing a point-of-care test that operates without the need for a blood culture and is a host response test that measures mRNA expression using artificial intelligence.
Last year, the firm announced a contract extension of $12.1 million from the Biomedical Advanced Research and Development Authority (BARDA), part of the U.S. Department of Health and Human Services, for continued development and clinical studies to support FDA clearance of the ViraBac EZ test. The test reads gene expression patterns in the immune system to identify whether a suspected infection is bacterial or viral and returns results in 30 minutes. Inflammatix is also developing an assay specifically for the early detection of sepsis.
Meanwhile, at AMP 2022, Immunexpress and Mechelen, Belgium-based Biocartis presented a poster detailing a multisite validation of ethylenediamine tetraacetic acid (EDTA) blood as a sample type for SeptiCyte Rapid running on the Idylla system. “Combined with the small 240 [microliter] blood volume requirement and the convenient and long storage conditions, the addition of the widely used EDTA blood tube as a validated sample type has the potential to greatly expand the clinical utility of this new near-patient sepsis diagnostic,” the study investigators concluded.