Should all patients be tested for SARS-CoV-2 before endoscopy?
Barriers to care should be avoided
In the AGA Institute Rapid Review and Recommendations on the Role of Pre-Procedure SARS-CoV-2 Testing and Endoscopy, the authors made a conditional recommendation for implementation of a preprocedure testing strategy, specifically for endoscopy centers where the prevalence of asymptomatic SARS-CoV-2 infection is intermediate (0.5%-2%).1 The authors stated that, in settings where testing is feasible and there is less perceived burden on patients and when the benefits outweigh the downsides (such as when false positives do not significantly outnumber the true positives), an endoscopy center should implement a preprocedure testing strategy. In addition to the prevalence of SARS-CoV-2 infection, which influences both the positive and negative predictive value of testing, the authors took into account the downstream consequences of test results, the pros and cons of a testing strategy, and the availability of PPE and tests.
The authors further clarify that, in areas with either low or high prevalence of asymptomatic cases, a pre-endoscopy testing strategy may not be informative. The group made a conditional recommendation against testing in these settings, highlighting concerns around the false positive rates in low-prevalence areas and potentially limited availability of tests and false negative rates in high-prevalence areas.
Early in the pandemic, because of the limited availability of tests, symptomatic or high-risk patients were given priority for SARS-CoV-2 testing. Since that time, over 180 different commercially available SARS-CoV-2 assays have become available, and many health systems have developed their own laboratory-developed tests.2 However, despite the aggressive efforts to ramp up test capacity, many endoscopy centers still struggle to obtain timely and reliable results. In light of continued challenges with testing, many endoscopy centers chose to not implement a pretesting strategy and instead proceed with N95 respirators or PAPRs for all procedures. Endoscopy centers that implemented a no-testing strategy emphasized the importance of ramping up productivity as quickly as possible and simultaneously reducing any barriers for patients.
They also highlighted reports that demonstrated a low yield of positive tests and that triaging could be performed equally well with the use of a symptom checklist or fever check. In one study from New York, among 623 asymptomatic patients tested before endoscopy during May and June, which was the height of the first surge, only 6 patients tested positive (overall percentage of SARS-CoV-2–positive tests in asymptomatic patients, 0.96%).3 Similarly, low rates of positive tests were reported in a center in Miami: Among a total of 396 PCR swabs in preparation for endoscopy, one patient had a positive PCR result (positive test rate, 0.25%).4
What are the implications for patients, providers, and endoscopy centers if a preprocedure testing strategy is not adopted? For individual patients, there is a potential for heightened concern about risk of infection from health care staff or other patients, but this may be offset by the decreased burden of testing. For health care professionals, it means that all procedures need to be performed with universal precautions and appropriate PPE. From an endoscopy operations perspective, there remain unanswered questions regarding room turnover and the necessity for negative pressure rooms. Symptom screening, which is locally required for all health visits, may help identify symptomatic patients, and thus, procedures for these individuals could be canceled and rescheduled or moved to negative pressure rooms (based on urgency).
Questions remain about the need to perform all procedures in negative pressure rooms or with prolonged room turnover to allow for a requisite number of air exchanges. There is general agreement among gastroenterologists that upper endoscopy is an aerosol-generating procedure. The passage of the scope near the pharynx (where the virus has a propensity for colonization and infection) may lead to aerosolization of infective particles and confer an increased risk of infection. However, it is unclear whether colonoscopy actually confers an increased risk. This would require that an asymptomatic patient would be infected with the SARS-CoV-2 virus and have viable viral particles in the colon that are released during the passage of flatus in high enough quantity to allow for aerosolization and transmission of infection. Conceptually, while there are potential risks associated with both endoscopy and colonoscopy, it is reassuring that we are not seeing published reports (or anecdotal evidence) suggesting high rates of COVID-19 infection among endoscopy staff or at endoscopy centers. Requiring prolonged room turnover between every procedure would negatively impact endoscopy efficiency and recovery of endoscopy centers.
Indeed, the aftermath of the COVID-19 pandemic will be far reaching. While telemedicine has helped mitigate some of the collateral damage, the disruption of cancer screening and surveillance programs may lead to high cancer-related morbidity and mortality. In one study evaluating the impact of COVID-19 on the U.S. cancer population, authors analyzed 6,227,474 Medicare Fee for Service claims (representing 5%-7% of the Medicare population) and found a substantial decrease in cancer screening and cancer care (therapy and surgeries).5 Screening for colon cancer was reduced by 75% in April.
Eliminating any potential barriers to care should be the highest priority. A requirement for patients to undergo preprocedure testing may contribute to increased anxiety and added costs and may further delay care. From a patient perspective, finding a testing facility, obtaining the test within 48-72 hours, self-isolating until the day of endoscopy, and dealing with the uncertainty of the test result may serve as additional barriers for completion of endoscopy. Moreover, the differential availability of testing may further exacerbate health inequities.
In the absence of pre-endoscopy testing for all patients, routine screening for symptoms, following COVID-19 infection precautions for all cases with strict adherence to physical distancing, and use of N95 (or PAPRs) during endoscopy may minimize viral transmission among patients and staff while maximizing patient adherence to endoscopy, ensuring resumption of endoscopic services, and ultimately mitigating some of the devastating impact of COVID-19 on population health.
Shahnaz Sultan, MD, MHSc, AGAF, FACG, is with the division of gastroenterology at the University of Minnesota in Minneapolis and the Center for Care Delivery and Outcomes Research at Minneapolis Veterans Affairs Healthcare System. She has no conflicts to declare.
References
1. Sultan S et al. Gastroenterology. 2020 Nov;159(5):1935-48.e5.
2. Food and Drug Administration. Emergency Use Authorization: Coronavirus Disease 2019 (COVID-19) EUA Information. 3. Dollinger MT et al. Gastroenterology. 2020;159:1962-4.
4. Forde JJ et al. Gastroenterology. 2020;159:1538-40.
5. Patt D et al. JCO Clin Cancer Inform. 2020 Nov;4:1059-71.
