Importance of serological testing in the convalescence phase in patients with pulmonary impairment due to COVID 19 - a health care workers analysis

  1. José Rodrigues Pereira
  2. Ilka Lopes Santoro
  3. Maria Silvia Biagioni Santos
  4. Andreia Padilha de Toledo
  5. Greice Elen Copelli
  6. Caroline Villela Galvão de França
  7. Edmundo Di Giaimo Caboclo

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Abstract

1

Since its discovery, more than 37 million people have been infected by SARS-CoV-2 with deaths around 1 million worldwide. The prevalence is not known because infected individuals may be asymptomatic. In addition, the use of specific diagnostic tests is not always conclusive, raising doubts about the etiology of the disease.

The best diagnostic method and the ideal time of collection remains the subject of study. The gold standard for diagnosing COVID 19 is the RT PCR molecular test, usually using an oropharynx and nasopharynx swab. Its sensitivity is 70% and drops significantly after the second week of symptoms. Serological tests, in turn, have increased sensitivity after 14 days, and can contribute to the diagnosis when SARS-CoV-2 infection is suspected, even with negative RT PCR.

Our study showed sensitivity and specificity of 100% of the serological test (ELISA method) for cases of viral pneumonia caused by the new coronavirus, suggesting that this test could assist in the diagnosis of pulmonary interstitial changes that have not yet been etiologically clarified. We found a greater immune response in men, regardless of the severity of symptoms. The greater the severity, the higher the levels of IgA and IgG, mainly found in patients with multilobar impairment and in need for oxygen. We concluded that the serological test collected around 30 days after the onset of symptoms is the best diagnostic tool in the convalescence phase, not only for epidemiological purposes, but also for the etiological clarification of pulmonary changes that have not yet been diagnosed.

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    SciScore for 10.1101/2021.03.24.20208835: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Thus, the most practical and representative material would be the nasal swab for both mild and severe cases, but with the caveat that its sensitivity is around 70%. A systematic review of the literature showed that the rate of false-negative results from RT-PCR is 29% (6). Out of the patients evaluated, 96% were positive for IgA (24/25) and 100% were positive for IgG (26/26), both of which were collected after 14 days. K Imai et al., using the immunochromatography technique, found IgM and IgG sensitivity for symptomatic patients with more than 14 days of symptoms of 95.8% and 65.2%, respectively. When the serological test is combined with chest tomography in symptomatic patients, sensitivity after two weeks reaches 100% (17). As the molecular analysis through RT-PCR can be falsely negative, the erroneous investigative conduct of the case would lead to misdiagnosis with new exams and unnecessary treatments, thus postponing fundamental interventions to prevent the patient from evolving with pulmonary fibrosis and permanent functional alteration. Patients confirmed for COVID 19 who presented pneumonia maintained presented pneumonia maintained evaluated around 30 days after the onset of symptoms, reaching 84.2% of DLCO in the pulmonary function test. (18) Previous studies with SARS showed that 52.4% of the patients who were hospitalized maintained abnormalities in the DLCO after 2 years (19). However, in other analysis, the improvement of this parameter occurred in 80.4% in 3 mon...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a protocol registration statement.

    About SciScore

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  2. Version published to 10.1101/2021.03.24.20208835 on medRxiv