Laboratory findings of COVID-19: a systematic review and meta-analysis

Abstract

The Coronavirus Disease (COVID-19) pandemic first broke out in December 2019 in Wuhan, China, and has now spread worldwide. Laboratory findings have been only partially described in some observational studies. To date, more comprehensive systematic reviews of laboratory findings on COVID-19 are missing. We performed a systematic review with a meta-analysis to assess laboratory findings in patients with COVID-19. Observational studies from three databases were selected. We calculated pooled proportions and 95% confidence interval (95% CI) using the random-effects model meta-analysis. A total of 1106 articles were identified from PubMed, Web of Science, CNKI (China), and other sources. After screening, 28 and 7 studies were selected for a systematic review and a meta-analysis, respectively. Of the 4,663 patients included, the most prevalent laboratory finding was increased C-reactive protein (CRP; 73.6%, 95% CI 65.0–81.3%), followed by decreased albumin (62.9%, 95% CI 28.3–91.2%), increased erythrocyte sedimentation rate (61.2%, 95% CI 41.3–81.0%), decreased eosinophils (58.4%, 95% CI 46.5–69.8%), increased interleukin-6 (53.1%, 95% CI 36.0–70.0%), lymphopenia (47.9%, 95% CI 41.6–54.9%), and increased lactate dehydrogenase (LDH; 46.2%, 95% CI 37.9–54.7%). A meta-analysis of seven studies with 1905 patients showed that increased CRP (OR 3.0, 95% CI: 2.1–4.4), lymphopenia (OR 4.5, 95% CI: 3.3–6.0), and increased LDH (OR 6.7, 95% CI: 2.4–18.9) were significantly associated with severity. These results demonstrated that more attention is warranted when interpreting laboratory findings in patients with COVID-19. Patients with elevated CRP levels, lymphopenia, or elevated LDH require proper management and, if necessary, transfer to the intensive care unit.

Keywords:

• COVID-2019
• SARS-CoV-2
• laboratory findings
• C-reactive protein
• lymphopenia
• lactate dehydrogenase

Disclosure statement

All authors report no potential conflicts of interest.

Author contributions

Zhang Zuli and Li Fengzeng formulated the research questions, designed the study, developed the preliminary search strategy, and drafted the manuscript. Hou Yulei and Li Detao refined the search strategy by conducting iterative database queries and incorporating new search terms. Li Fengzeng and Li Detao searched and collected the articles, then conducted the quality assessment. All authors critically reviewed the manuscript for relevant intellectual content. All authors have read and approved the final version of the manuscript.

Additional information

Funding

This work was supported by the First Affiliated Hospital of Chongqing Medical University [grant number HLJJ2014-21].