Asymptomatic hospital admissions

Patients in this category would need testing prior to hospital admission in order to prevent nosocomial COVID-19 transmission and to triage patients appropriately within the hospital setting.66,67 These patients would not have symptoms of COVID-19 and would be attending routine healthcare appointments or planned surgeries; these appointments are not considered as urgent care.

Current practices

Point-of-care or centralized NAATs are generally used to test patients prior to admission. Patients may be able to isolate whilst they await their test results, making centralized testing possible in some settings. The urgency of the care that is required also determines whether the patient should have a rapid point-of-care test or whether a centralized option would be acceptable. As patients are asymptomatic there is no need for repeat testing; if they test positive, they should isolate for 14 days and then retest for COVID-19.67 As these patients are asymptomatic, antigen tests may not be adequately sensitive to detect COVID-19 (Table 1).4,53,68 In this setting, if patients do have a positive antigen test result they should be treated similarly to patients with a positive NAAT, requiring them to isolate for 14 days and retest (Figure 1).

Key considerations

NAATs are the most sensitive method for detection of SARS-CoV-2 and would maximally prevent the spread of infection to the healthcare system. A disadvantage of using NAATs in this setting is that studies have shown prolonged NAAT positivity in patients who are no longer symptomatic following infection, and it may be that non-infectious virus is detected.50,69,70 71
Antigen testing is not as sensitive as a NAAT, particularly in asymptomatic individuals, and as such, there is the possibility that false-negative tests may leave the healthcare system exposed to infection.72 However, this risk is currently mitigated by the universal COVID-19 precautions utilized in healthcare settings and will be further mitigated once the healthcare workforce is vaccinated. Antigen tests would be more useful if they could reliably indicate whether or not a patient is infectious, preventing unnecessary hospitalization. More information regarding how diagnostics tests relate to infectivity is needed before this is possible.