Better diagnostic tools could have a major impact in patient care
At this year’s Clinical Virology Symposium (CVS), Xiaotian Zheng’s spoke about developing and evaluating a laboratory developed test (LDT) on the ARIES® System for detecting enteroviruses in blood samples from children. The enterovirus study began with a plea from his hospital’s emergency department to decrease the number of painful, invasive spinal taps performed on children. Zheng, Director of Microbiology at the Ann & Robert H. Lurie Children’s Hospital of Chicago, knew that suspected enterovirus infections contribute significantly to the number of cerebrospinal fluid samples collected from patients. Enterovirus testing can be a challenge due to the variability of viral load, and non-specific symptoms. In addition, current tests require the collection and use of cerebrospinal fluid instead of less invasive alternative specimens.
Enteroviruses are a large, diverse group of small RNA viruses. Members include poliovirus, Coxsackieviruses, and rhinoviruses, among many others. There are approximately one billion cases annually around the world. Molecular testing is used to diagnose enteroviruses, but in addition to requiring cerebrospinal fluid, many current PCR assays are cross-reactive for more than one virus, Zheng explained during the presentation at CVS. He closely followed scientific publications from European labs reporting success in diagnosing enteroviruses from blood samples, but no such studies had been performed in the U.S.
Blood Samples for Enterovirus Testing
Zheng set out to determine the utility of blood samples for enterovirus testing, evaluating the ARIES® System in the process. The study included two groups of blood samples: 10 from children found to be enterovirus-positive from cerebrospinal fluid testing, and 227 collected from the hospital’s general patient population, with no specific focus on suspected enterovirus cases. The LDT that his team ran on the ARIES® System performed well in an assessment of limit of detection. It also displayed no cross-reactivity between the many enterovirus types detected. “The assay seemed to be sensitive and also specific,” Zheng said.
Most importantly, the study found that the assay run on the ARIES® System could detect enteroviruses from blood in the majority of cases. Seven of the 10 known enterovirus-positive cases were called positive from blood samples, information that could significantly reduce the number of spinal taps required for pediatric patients. Among the blood samples collected from the broader patient group, about 10 percent were reported enterovirus-positive; Zheng noted that follow-up studies are needed, but it could be that enterovirus infection is more widespread than expected, and that better diagnostic tools could have a major impact in patient care.
Improved Testing with ARIES
The project also served to familiarize Zheng’s team with the ARIES® System, which they appreciated for its small footprint and integrated computer. “The automation improved our laboratory testing significantly,” Zheng said, comparing it to other real-time PCR testing platforms that require much more time and technical expertise to run. A big advantage he found is that “the platform can accommodate both on-demand and batch testing at the same time,” he said. Now his lab can handle samples as they come in, rather than having to prioritize or delay certain samples based on that day’s orders.
Disclosure: The ARIES® instrument, reagents, and cassettes were provided by Luminex for this study.
Luminex does not endorse the use of any LDT for diagnostic use.
Luminex and ARIES are trademarks of Luminex Corporation, registered in the U.S. and other countries. ARIES Systems are class 1(I) laser products.