Coronavirus disease (COVID-19) technical guidance by WHO Laboratory testing for COVID-19

Laboratory testing for coronavirus disease 2019 (COVID-19) in suspected human cases. Interim guidance 2 March 2020 1. Introduction The decision to test should be based on clinical and epidemiological factors and linked to an assessment of the likelihood of infection. PCR testing of asymptomatic or mildly symptomatic contacts can be considered in the assessment of individuals who have had contact with a COVID-19 case. Screening protocols should be adapted to the local situation. The case definitions are being regularly reviewed and updated as new information becomes available. For the WHO suspect case definition see: Global Surveillance for human infection with coronavirus disease (COVID-2019) (10) . Several coronaviruses can infect humans, the globally endemic human coronaviruses HCoV-229E, HCoV-NL63, HCoV-HKU1 and HCoV-OC43 that tend to cause mild respiratory disease, and the zoonotic Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV) that have a higher case fatality rate. In December 2019, a cluster of patients with a novel coronavirus was identified in Wuhan, China (1). Initially tentatively named 2019 novel coronavirus (2019-nCoV), the virus has now been named SARS-CoV-2 by the International Committee of Taxonomy of Viruses (ICTV) (2). This virus can cause the disease named coronavirus disease 2019 (COVID-19). WHO refers to the virus as COVID-19 virus in its current documentation. Rapid collection and testing of appropriate specimens from patients meeting the suspect case definition for COVID-19 is a priority for clinical management and outbreak control and should be guided by a laboratory expert. Suspect cases should be screened for the virus with nucleic acid amplification tests (NAAT), such as RT-PCR. The purpose of this document is to provide interim guidance to laboratories and stakeholders involved in COVID-19 virus laboratory testing of patients. If testing for COVID-19 is not yet available nationally, specimens should be referred. A list of WHO reference laboratories providing confirmatory testing for COVID-19 and shipment instructions are available in Section 4 of the following webpage: https://www.who.int/emergencies/diseases/novel- coronavirus-2019/technical-guidance/laboratory- guidance. Existing WHO documents have been consulted for drafting this interim guidance, including the interim guidance on laboratory testing for MERS (3-9). Information on human infection with the COVID-19 virus is evolving and WHO continues to monitor developments and revise recommendations as necessary. Feedback is welcome and can be sent to [email protected]. If case management requires, patients should be tested for other respiratory pathogens using routine laboratory procedures, as recommended in local management guidelines for community-acquired pneumonia. Additional testing should not delay testing for COVID-19. As co-infections can occur, all patients that meet the suspect case definition should be tested for COVID-19 virus regardless of whether another respiratory pathogen is found. 2. Laboratory testing guiding principles for patients who meet the suspect case definition 1