Benefits and limitations of serological assays in COVID-19 infection

Abstract

Accurate and rapid diagnostic tests are critical for achieving control of coronavirus disease 2019 (covid-19), a pandemic illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diagnostic tests for covid-19 fall into two main categories: molecular tests that detect viral RNA, and serological tests that detect anti-SARS-CoV-2 immunoglobulins. Reverse transcriptase polymerase chain reaction (RT-PCR), a molecular test, has become the gold standard for diagnosis of covid-19; however, this test has many limitations that include potential false negative results, changes in diagnostic accuracy over the disease course, and precarious availability of test materials. Serological tests have generated substantial interest as an alternative or complement to RT-PCR and other Nucleic acid tests in the diagnosis of acute infection, as some might be cheaper and easier to implement at the point of care. A clear advantage of these tests over RT-PCR is that they can identify individuals previously infected by SARS-CoV-2, even if they never underwent testing while acutely ill. Many serological tests for covid-19 have become available in a short period, including some marketed for use as rapid, point-of-care tests. The pace of development has, however, exceeded that of rigorous evaluation, and important uncertainty about test accuracy remains.

SARS-CoV-2 Seroprevalence and Neutralizing Antibody Response after the First and Second COVID-19 Pandemic Wave in Croatia

“…However, some patients in the early acute phase of COVID-19 may be missed (serological "window" period). Molecular diagnostics (RT-PCR) in seronegative individuals allows additional prevalence estimates, including the acute infections without detectable antibodies [ 39 ]. In this study, data on the SARS-CoV-2 RT-PCR were not available, which should be pointed out and considered when interpreting the seroprevalence results, especially in seronegative individuals.…”

A Comprehensive Review of Detection Methods for SARS-CoV-2

“…COVID-19 has been detected with several serological tests, some of which were marketed as point-of-care and rapid methods so far. However, test accuracy results remain challenging [ 11 ]. The serological test of COVID-19 provides information on the type and concentration levels of various immunoglobulins (IgA, IgM, and IgG) produced due to infection by SARS-CoV-2.…”

Practicability of serological assays for upscaling COVID-19 laboratory testing in Africa

“…Based on applicability, SARS-CoV-2 antigen-based tests have developed and proved to be rapid, easy to perform with a less than 30 minutes turn-around-time when compared with the NAATs [ 18 ]. These rapid tests are vital either as alternatives or in supplementing the role of nucleic acid-based tests in the confirmation, management and the signaling of cases to be isolated in order to prevent viral transmission.…”

“…These rapid tests are vital either as alternatives or in supplementing the role of nucleic acid-based tests in the confirmation, management and the signaling of cases to be isolated in order to prevent viral transmission. Furthermore, COVID-19 serological assays are less technical, and the quality of specimen required is relatively lesser than those of RT-PCR tests [ 18 ]. Despite these advantages, the applicability of serological-based tests is limited as these kits cannot serve for the screening of COVID-19 due to their low diagnostic performance at the early stage of infection [ 18 ].…”