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Coronavirus disease 2019 (COVID-19) emerged in December 2019 in Wuhan, China; it has since caused a pandemic, with more than 10,000 confirmed cases (> 800,000 tests) in Korea as of May 2020. Real-time reverse transcription poly-merase chain reaction (RT-PCR) is currently the most commonly used method for the diagnosis of COVID-19 worldwide. The Korean Society for Laboratory Medicine and Korea Centers for Dis-ease Prevention and Control regularly update the guidelines for COVID-19 diagnosis. Emergency use authorization for some laboratory diagnostic kits has been granted, enabling the timely diagnosis and treatment of COVID-19, and the isolation of infected patients. Due to the collective efforts of the government, medical professionals, local authorities, and the public, Korea's response to the COVID-19 outbreak has been accepted widely as a model. Here, we summarize the currently available laboratory tests for COVID-19 diagnosis. Although RT-PCR tests are used widely to confirm COVID-19, anti-body tests could provide information about immune responses to the virus.

Our hospital experienced the first healthcare-associated COVID-19 outbreak in Seoul at the time the first COVID-19 cases were confirmed in Korea. The first confirmed COVID-19 patient was a hospital personnel who was in charge of transferring patients inside our hospital. To contain the virus spread, we shutdown our hospital, and tested all inpatients, medical staff members, and employees. We retrospectively analyzed the results of SARS-CoV-2 RT-PCR testing according to the contact history, occupation, and presence of respiratory symptoms. Closed-circuit television (CCTV) was reviewed in the presence of an epidemiologist to identify individuals who came into contact with confirmed COVID-19 patients. A total of 3,091 respiratory samples from 2,924 individuals were obtained. Among 2,924 individuals, two inpatients, and one caregiver tested positive (positivity rate, 0.1%). Although all confirmed cases were linked to a general ward designated for pulmonology patients, no medical staff members, medical support personnel, or employees working at the same ward were infected. Contact with confirmed COVID-19 cases was frequent among inpatients and medical support personnel. The most common contact area was the general ward for pulmonology patients and medical support areas, including clinical and imaging examination rooms. Finally, the total number of hospital-associated infections was 14, consisting of four diagnosed at our hospital and ten diagnosed outside the hospital. The robust control of the COVID-19 outbreak further minimized the transmission of SARS-CoV-2 in the hospital and local communities. However, there was also a debate over the appropriate period of hospital shutdown and testing of all hospital staff and patients. Future studies are required to refine and establish the in-hospital quarantine and de-isolation guidelines based on the epidemiological and clinical settings.