Biochemical, Serological and Immunological Tests for Diagnosis of Coronavirus Disease 2019 (COVID-19) Patients: A Comprehensive Systematic Review and Meta-analysis.

Background: Recent studies have suggested the role of primary laboratory tests in addition to clinical symptoms for patients suspected to have coronavirus disease 2019 (COVID-19), which play a significant role in the diagnosis of COVID-19. However, the results of these studies are contradictory. The present study was conducted to evaluate biochemical, serological, and immunological tests for the diagnosis of COVID-19 patients.

Methods: This study was presented in accordance with the PRISMA protocol. This protocol is registered with the code CRD42019145410 in PROSPERO. We conducted a comprehensive literature search in databases, including Web of Science, PubMed/Medline, CINAHL Scopus, Cochrane Library, EMBASE, Science Direct, and EBSCO to find citations from the beginning of January 2019 until the beginning of April 2020 without any restrictions.

Results: Finally, 51 studies, including 5,490 COVID-19 patients, were included in the present metaanalysis. The prevalence of different factors observed in laboratory findings was as follows: the prevalence of lymphopenia in patients with COVID-19 accounted for 51.6% (95% CI: 44.0-59.1), elevated C-reactive protein (CRP) was 63.6% (95% CI: 57.0-69.8), elevated erythrocyte sedimentation rate (ESR) was 62.5% (95% CI: 50.1-73.5), elevated tumor necrosis factor alpha (TNFα) was 28.7% (95% CI: 9.0-62.1), elevated serum amyloid-A level was 74.7% (95% CI: 50.0-89.7), elevated procalcitonin level was 72.6% (95% CI: 58.1-83.5), elevated interleukin-6 level was 59.9% (95% CI: 48.2-70.5), reduced CD3 level was 68.3% (95% CI: 50.1-82.2), reduced CD4 level was 62.0% (95% CI: 51.1- 71.6), elevated lactate dehydrogenase (LDH) level accounted for 53.1% (95% CI: 43.6-62.4), elevated brain natriuretic peptide (BNP) accounted for 48.9% (95% CI: 30.4-67.7), reduced albumin and reduced pre-albumin levels in patients with COVID-19 were estimated to be 54.7% (95% CI: 38.1-70.2) and 49.0% (95% CI: 26.6-71.8), and D-dimer level was 44.9% (95% CI: 31.0-59.6).

Conclusion: The results show lymphopenia, elevated ESR level, elevated CRP level, elevated serum amyloid-A, elevated TNFα, elevated procalcitonin level, elevated interleukin-6 level, reduced CD3, reduced CD4, elevated BNP, elevated LDH, reduced albumin, reduced pre-albumin, and elevated Ddimer levels as the most common findings at the time of admission.