BackgroundIn early December 2019, the first patient with COVID-19 pneumonia was found in Wuhan, Hubei Province, China. Recent studies have suggested the role of primary laboratory tests in addition to clinical symptoms for suspected patients, which play a significant role in the diagnosis of COVID-19. Therefore, the present study was conducted to evaluate laboratory findings in COVID-19 patients.Data SourcesPubMed/Medline, Scopus, EMBASE, Web of Science (ISI), Cochrane Library, Ovid, Science Direct, CINAHL and EBSCO.Study SelectionCross-sectional of adverse outcomes stratified by the status of ICLs were selected.Data ExtractionThe prevalence of available variables for laboratory tests were extracted.ResultsFinally, 52 studies involving 5490 patients with COVID-19 entered the meta-analysis process. The prevalence of leukopenia, lymphopenia, elevated c-reactive protein (CRP), elevated erythrocyte sedimentation rate (ESR), elevated serum amyloid A, elevated ferritin was estimated to be 20.9% (95%CI: 17.9-24.3), 51.6% (95%CI: 44.0-59.1), 63.6% (95%CI: 57.0-69.8), 62.5% (95%CI: 50.1-73.5), 63.6% (95%CI: 57.0-69.8), 62.5% (95%CI: 50.1-73.5), 74.7% (95%CI: 50.0-89.7), and 72.6% (95%CI: 58.1-83.5), respectively. The prevalence of elevated interleukin-6 was 59.9% (95%CI: 48.2-70.5), CD3 was 68.3% (95%CI: 50.1-82.2), reduced CD4 was 62.0% (95%CI: 51.1-71.6), reduced CD8 was 42.7% (95%CI: 32.2-53.9). The prevalence of elevated troponin-I was 20.6% (95%CI: 9.0-40.5), elevated creatine kinase-MB (CKMB) was 14.7% (95%CI: 7.1-28.0), elevated brain natriuretic peptide (BNP) was 48.9% (95%CI: 30.4-67.7), elevated blood urea nitrogen was 13.1% (95%CI: 6.6-24.4),, elevated creatinine was 7.2% (95%CI: 4.4-11.8), elevated lactate dehydrogenase (LDH) was 53.1% (95%CI: 43.6-62.4), hyperglycemia was 41.1% (95% CI: 28.2-55.5), elevated total bilirubin was 48.9% (95%CI: 30.4-67.7), reduced albumin was 54.7% (95%CI: 38.1-70.2), reduced pre-albumin was 49.0% (95%CI: 26.6-71.8), and reduced PT was 53.1% (95% CI: 43.6-62.4), and D-dimer was 44.9% (95%CI: 31.0-59.6).ConclusionThis study provides a comprehensive description of laboratory characteristics in patients with COVID-19. The results show that lymphopenia, elevated CRP, elevated ESR, elevated ferritin, elevated serum amyloid A, elevated BNP, reduced albumin, reduced pre-albumin, reduced CD3, reduced CD4, reduced CD8, elevated D-dimer, reduced PT, elevated interleukin-2, elevated interleukin-6, elevated LDH and hyperglycemia are the common findings at the time of admission.