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The Value of Syndromic Testing for Gastroenteritis

The patient was a healthy 26-year-old with no chronic conditions. He arrived at the ER complaining of acute diarrhea and with mild dehydration. He received an abdominal CT scan and clinicians considered the possibility of irritable bowel syndrome, Meckel diverticulum, or Chrohn’s disease.

The answer turned out to be a co-infection of Salmonella, Plesiomonas, and norovirus, all of which could have been discovered earlier, although it would have been difficult and time-consuming to identify all three pathogens with traditional testing methods.

The Impact of Gastroenteritis

At some point during our lives, virtually every person will experience the symptoms of gastroenteritis: diarrhea that may be accompanied by nausea, vomiting, and abdominal cramps. Gastroenteritis, an inflammation of the gastrointestinal tract, is strikingly common, with an estimated 179 million episodes of diarrhea occurring in the US each year.1

Gastroenteritis is often caused by infectious agents, including bacteria, viruses, and parasites. These pathogens can be spread via contaminated food or water, on contaminated surfaces, or from person to person. Infectious diarrheal disease can range from a minor infection to a serious, life-threatening illness.

In the United States, foodborne diarrheal illness results in more than 128,000 hospitalizations and 3,000 deaths a year.2 GI illness also exacts a large financial toll, with foodborne illnesses alone costing an estimated $6 billion each year in the US for medical care and lost productivity.3

Unfortunately, overlapping symptomology makes it difficult to determine the probable cause of gastroenteritis based on clinical presentation alone. Furthermore, incorrect diagnosis may lead to unnecessary or incorrect treatment, additional procedures, worsening illness, sequelae, and secondary transmission.

Testing Guidelines

Given how common diarrheal illness is, it can be difficult to know which patients to test for infectious pathogens. The Infectious Disease Society of America and American College of Gastroenterology offer several guidelines for determining when it is appropriate to test:4,6

  • During known or suspected outbreaks
  • Individuals at high risk of spreading disease to others
  • Cases presenting with dysentery, fever, severe abdominal cramping or tenderness, moderate to severe disease, symptoms lasting more than seven days, or signs of sepsis
  • Immunocompromised patients, especially those with moderate or severe primary or secondary immune deficiencies

When a patient is at a high risk of spreading the disease to others, and during known or suspected outbreaks, diagnostic best practices include using stool culture in conjunction with culture-independent methods. Overall, the use of culture-independent testing methods is recommended at least as an adjunct to traditional methods when available.6

The Trouble With Traditional Stool Testing

Clinicians and laboratories have a variety of methods to choose from when testing for enteric pathogens. Each of these methods comes with unique challenges and tradeoffs.

Stool culture, for instance, is a high-complexity test that can take days for results. And in the end, with a yield of only 1.5%-2.9%, it doesn’t often provide actionable answers.

If parasites are suspected, an ova and parasite exam may be ordered. But this high-complexity test has a relatively low sensitivity and a low yield of about 1.4%.

Traditional PCR is a high-complexity test that requires a specialized laboratory. Like immunoassays, traditional PCR can test for individual pathogens or a limited range of pathogens. While results may be available within hours, traditional PCR also offers a relatively low diagnostic yield compared to multiplex testing.

For laboratories, traditional stool testing is time consuming and usually needs to be performed by laboratorians with technical expertise. For clinicians, the lengthy time-to-result for traditional testing methods, combined with low yield and a potential need for serial testing, often forces them to make treatment decisions without laboratory results.

What does all of this mean for patients? With traditional testing, patients may experience longer lengths of stay, additional diagnostic procedures, unnecessary antibiotics, and prolonged treatment. And in the end, they may be left with continuing uncertainty about what’s actually making them sick.

The Syndromic Approach

The BIOFIRE® FILMARRAY® Gastrointestinal (GI) Panel is a game changer for infectious gastroenteritis. The multiplex PCR BIOFIRE GI Panel follows a syndromic testing approach, identifying a comprehensive menu of 22 gastrointestinal pathogens, including bacteria, viruses, and parasites—with results in about an hour. The BIOFIRE GI Panel is highly accurate, with an overall sensitivity of 98.5% and specificity of 99.2%.9 

The BIOFIRE GI Panel requires just one specimen (stool in Cary Blair medium) and two minutes of hands-on time. It’s easy to perform, with extraction, amplification, and detection all occurring within the pouch. A Detected or Not Detected call for each pathogen is provided in one easy-to-read report.

With traditional testing, diagnosing gastroenteritis is a guessing game. Will the right test be ordered? Will additional tests need to be ordered—and which ones? Will results be available in time to impact treatment decisions? Without solid answers, patient care may be compromised, increasing the risk of adverse outcomes and patient dissatisfaction.

On the other hand, syndromic testing can lead to better informed therapy. With fast answers on a comprehensive menu, syndromic testing increases the chance of actually identifying a pathogen. Actionable answers help to reduce additional testing, inform therapy decisions and antibiotic stewardship efforts, and aid in patient management decisions such as admission, isolation, and cohorting.

Benefits of Syndromic Testing with the BIOFIRE GI Panel

Operational Benefits

The BIOFIRE GI Panel can streamline workflow by providing faster and more comprehensive test results. With a detection rate of ~35%, the BIOFIRE GI Panel detects more pathogens than traditional testing, which has a detection rate of 6%.10

Furthermore, use of the BIOFIRE GI Panel may help optimize hospital resources while improving patient care. Compared to traditional diagnostic methods, syndromic testing from the BIOFIRE GI Panel has been shown to:11

  • Decrease the number of additional stool tests from 3 to ~1
  • Reduce the average time-to-result 84%
  • Reduce patient length of stay when results were known at time of discharge

Clinical Benefits

Because traditional stool testing methods are slow and lack sensitivity, clinicians often have to make therapy decisions without a lab result. However, use of the rapid and comprehensive BIOFIRE GI Panel results in 41% more targeted therapy and less 11% less antibiotics prescribed.10,12 Additionally, a study found the median time from collection to initiation of antimicrobial therapy was 50 hours faster with the BIOFIRE GI Panel compared to those diagnosed by culture.10

Syndromic testing with the BIOFIRE GI Panel can also:

  • Shorten length of stay1
  • Reduce downstream procedures like endoscopies, X-rays, CT scans, and ultrasounds.11,12

Economic Benefits

With reduced lengths of stay and reductions in radiologic tests performed, the BIOFIRE GI Panel has the potential to lower healthcare costs: observed savings per patient reached $293.61.11 Worth noting, this figure doesn’t account for a reduction in laboratory testing when serial and repeat tests are avoided.

Bottom Line

Gastrointestinal illness is incredibly common and presents a heavy burden for laboratories and health systems. On top of that, traditional testing methods come with several downsides: they are often slow, labor intensive, and ultimately may not provide rapid answers. That’s why the BIOFIRE GI Panel is a game-changer—it’s fast, comprehensive, and accurate, which can optimize healthcare and laboratory resources while leading to better patient care.

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References

  1. Torres-Miranda D et al. BMC Gastro. (2020): 20:246
  2. Barr, W et al. Am Fam Physician. (2014): 89(3):180-189.
  3. Guerrant RL et al. Clin Infect Dis. (2001) :32:331-351.
  4. Shane AL et al. Clin Infect Dis. (2017): 65(12):e45–e80.
  5. Connor BA et al. J Travel Med 2013;20:303-312.
  6. Riddle MS et al. Am J Gastroenterol. (2016): 111:602-622.
  7. Polage, CR et al. JCM (2011): 591-6.
  8. Zhang, J et al. FPD (2019): 788-798.
  9. The stated performance is the overall aggregate of the prospective data in the clinical study.
  10. Cybulski et al. CID. (2018): 13;67(11):1688-1696.
  11. Beal S, et al. JCM. (2018): 56 (1): JCM. 01457-17.
  12. Axelrad JE, et al. JCM. (2019): 57(3): e01775-01718.

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