SARS-CoV-2 laboratory diagnostic methods: a systematic review

Nunes, Rúben; Melo, Carolina; Martins, Diana; Mendes, Fernando

BACKGROUND: The new SARS-CoV-2 is a single‐stranded RNA β-coronavirus, and it is comprising by structural proteins (N), (S), (E) and (M). Timely and accurate detection is necessary for spread control of SARS-CoV-2 infection, avoiding inaccurate outcomes. Therefore, in this systematic review, it is purpose to evaluate a set of laboratory diagnostic techniques and methods, analyse their specificity, sensitivity, contributing to improve detection rates and reduce false negative and false positive diagnostic results. METHODS: In this review, we used literature available on the indexed search database ‘PubMed’, concerning the following keywords: ‘SARS-CoV-2’, ‘Specimen handling’, ‘Cell Culture Technique’, ‘Viral Antigen’, ‘Immunoassay’, ‘NAAT’ according to Medical Subject Headings Mesh and applying the Prisma Diagram methodology. RESULTS: DD-PCR and CRISPER had more promising results, but they are unconventional and expensive NAAT methods, the usage of the target RdRp/He gene has exhibited very encouraging results improving sensitivity and specificity. After the onset of symptoms, the sensitivity of the immunoassay varies considering of blood collection day. The antigen detection test showed the highest specificity reached, however is sensitivity is lower compared to NAAT assays. CONCLUSIONS: In summary, RT-PCR still considered the gold standard and precisely detects the presence of virus RNA, although with some flaws in sensitivity, while the serological tests identify a previous infection by the virus, detecting antibodies, allowing the kinetic and immunological studies, not being able to use as a diagnostic method. The molecular point of care testing equipment’s revelled be the future in the rapid and accurately diagnosis of SARS-CoV-2.