Clinical Significance of an IgM and IgG Test for Diagnosis of Highly Suspected COVID-19

Abstract

Background: Nucleic acid detection and CT scanning have been reported in COVID-19 diagnosis. Here, we aimed to investigate the clinical significance of IgM and IgG testing for the diagnosis of highly suspected COVID-19.Methods: A total of 63 patients with suspected COVID-19 were observed, 57 of whom were enrolled (24 males and 33 females). The selection was based on the diagnosis and treatment protocol for COVID-19 (trial Sixth Edition) released by the National Health Commission of the People's Republic of China. Patients were divided into positive and negative groups according to the first nucleic acid results from pharyngeal swab tests. Routine blood tests were detected on the second day after each patient was hospitalized. The remaining serum samples were used for detection of novel coronavirus-specific IgM/IgG antibodies.Results: The rate of COVID-19 nucleic acid positivity was 42.10%. The positive detection rates with a combination of IgM and IgG testing for patients with COVID-19 negative and positive nucleic acid test results were 72.73 and 87.50%, respectively.Conclusions: We report a rapid, simple, and accurate detection method for patients with suspected COVID-19 and for on-site screening for close contacts within the population. IgM and IgG antibody detection can identify COVID-19 after a negative nucleic acid test. Diagnostic accuracy of COVID-19 might be improved by nucleic acid testing in patients with a history of epidemic disease or with clinical symptoms, as well as CT scans when necessary, and serum-specific IgM and IgG antibody testing after the window period.

Rapid diagnostic methods for SARS-CoV-2 (COVID-19) detection: an evidence-based report

“…The initial positive nucleic acid test and the lung changes seen on computed tomography (CT) scans must be compared and checked. Positive cases typically have a low lung CT, which is similar to a reverse halo sign, but this should be supported by several other nucleic acid tests [ 31 , 32 ].…”

“…CT is a non-invasive imaging technique that can detect certain trademark indications in the lung associated with the novel coronavirus SARS-CoV-2 [ 32 , 53 ]. As a result, computed tomography can be an effective method for the early detection and screening for COVID-19 positive patients.…”

Evaluation of Diagnostic Modalities for SARS-Cov-2: A Review Study

“…However, the positive diagnostic rate of the combination of IgM and IgG detection was 72.73% in 33 patients with COVID-19 negative RT_PCT results and it was 87.50% in 24 patients with COVID-19 negative RT-PCT results. 11 Nucleic Acid Detection: PCR Nowadays, precise genome detection serves a substantial function in COVID-19 diagnosis. In this regard, RT-PCR is the primary technique for detection of SARS-CoV-2 nucleic acid.…”

“…Today, serum immunoglobulin assays, nucleic acid sequencing, and chest imaging are recognized as the standard diagnostic methods. 11 The definite diagnosis of COVID-19 is made once the oropharyngeal swab collected from a suspected case is confirmed to contain viral nucleic acid, 8,12 which is complemented by additional tests such as measuring the serum levels of Immunoglobulin M (IgM) and Immunoglobulin G (IgG) against the virus. 13 The serologic method has several advantages because it is simple to perform and yields a high sensitivity.…”

“…13 The serologic method has several advantages because it is simple to perform and yields a high sensitivity. 11 Quantitative realtime reverse transcriptase-polymerase chain reaction assay, or simply quantitative reverse transcription polymerase chain reaction (RT-qPCR), has been extensively used for detecting SARS-CoV-2 RNA in the respiratory secretions of suspected cases. 6 Based on available kits, this method offers a sensitivity of 45%-60%; therefore, repeated testing is recommended in the early stages of the disease.…”