I refer to the letter from Mr Michael Smith published on May 25, requesting comment from the Hospital Authority in response to his suggestions (“ Speed up Covid-19 testing for airport arrivals ”). In response to the Covid-19 pandemic, the Hospital Authority has joined hands with the Department of Health to adopt the strategy of “early case detection, isolation and diagnosis”. The tests for asymptomatic inbound travellers at the airport, mentioned by Mr Smith, are in fact provided by the Public Health Laboratory Service Branch of the Department of Health. At the same time, Hospital Authority laboratories have conducted over 90,000 tests, mainly for inpatients and outpatients of public hospitals and clinics; symptomatic inbound travellers at the airport ; and symptomatic persons under quarantine orders as referred by the Department of Health. To meet operational needs, different types of detection platforms have been used in public hospital laboratories for Covid-19 tests. The conventional polymerase chain reaction (PCR) platform can handle around 90 specimens at the same time with a turnaround time of six to eight hours. There is also a rapid PCR test that allows the flexibility of handling single or a small number of tests at one time, for instance at the “triage and test” centres of the accident and emergency departments, or before some emergency operating procedures. While the run time of the latter test machine is around 45 minutes, the turnaround time including specimen preparation and transport is around two to three hours in all. In choosing the type of test, due consideration is given to the number of patient specimens, the urgency of the tests to facilitate clinical decisions on isolation, treatment or discharge, and other factors. Typically, the Hospital Authority has been conducting 1,000 tests every day, with a maximum of around 2,000 tests during peak times. Dr Vivien Chuang, chief manager (Infection, Emergency and Contingency), Hospital Authority