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.