Clinical applications of detecting IgG, IgM or IgA antibody for the diagnosis of COVID-19: A meta-analysis and systematic review.

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 2021;104:415-422
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Plain language summary

The rapidly spreading nature of COVID-19 has put an emphasis on the importance of fast diagnosis. Gold standard diagnosis is through reverse transcription polymerase chain reaction (RT-PCR) tests, which aims to detect the presence of COVID-19. However, challenges with collection techniques and when in the disease lifecycle these tests are taken, can affect their reliability, highlighting a need for alternative methods of testing. Other testing methods exist, which involve testing the body’s own immune response to the presence of COVID-19, however these may also have their limitations. This systematic review and meta-analysis aimed to determine the effectiveness of testing the body’s own immune reaction for the presence of COVID-19. The results showed that testing the body’s immune reaction was effective, however if the person being tested is at an early stage in the disease, then it may be misdiagnosed. This study could be used by healthcare professionals to understand that the use of any type of COVID-19 testing may have its limitations, and although a person may test negative, there is still a possibility that they have the infection if symptoms exist

Abstract

BACKGROUND The coronavirus disease 2019 (COVID-19) pandemic has had a devastating impact worldwide, and timely detection and quarantine of infected patients are critical to prevent spread of disease. Serological antibody testing is an important diagnostic method used increasingly in clinics, although its clinical application is still under investigation. METHODS A meta-analysis was conducted to compare the diagnostic performance of severe acute respiratory syndrome coronavirus-2 antibody tests in patients with COVID-19. The test results analysed included: (1) IgM-positive but IgG-negative (IgM+IgG-); (2) IgG-positive but IgM-negative (IgG+IgM-); (3) both IgM-positive and IgG-positive (IgM+IgG+); (4) IgM-positive without IgG information (IgM+IgG+/-); (5) IgG-positive without IgM information (IgG+IgM+/-); (6) either IgM-positive or IgG-positive (IgM+ or IgG+); and (7) IgA-positive (IgA+). RESULTS Sixty-eight studies were included. Pooled sensitivities for IgM+IgG-, IgG+IgM-, IgM+IgG+, IgM+IgG+/-, IgG+IgM+/-, and IgM+ or IgG+ were 6%, 7%, 53%, 68%, 73% and 79% respectively. Pooled specificities ranged from 98% to 100%. IgA+ had a pooled sensitivity of 78% but a relatively low specificity of 88%. Tests conducted 2 weeks after symptom onset showed better diagnostic accuracy than tests conducted earlier. Chemiluminescence immunoassay and detection of S protein as the antigen could offer more accurate diagnostic results. DISCUSSION These findings support the supplemental role of serological antibody tests in the diagnosis of COVID-19. However, their capacity to diagnose COVID-19 early in the disease course could be limited.

Lifestyle medicine

Fundamental Clinical Imbalances : Immune and inflammation
Patient Centred Factors : Mediators/IgA testing
Environmental Inputs : Microorganisms
Personal Lifestyle Factors : Not applicable
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable

Metadata

Nutrition Evidence keywords : IgM ; IgG ; IgA