Background To date, several clinical laboratory parameters associated with Coronavirus disease 2019 (COVID-19) severity have been reported. However, these parameters have not been observed consistently across studies. The aim of this review was to assess clinical laboratory parameters which may serve as markers or predictors of severe or critical COVID-19. Methods and findings We conducted a systematic search of MEDLINE, Embase, Web of Science, CINAHL and Google Scholar databases from 2019 through April 18, 2020, and reviewed bibliographies of eligible studies, relevant systematic reviews, and the medRxiv pre-print server. We included hospital-based observational studies reporting clinical laboratory parameters of confirmed cases of COVID-19 and excluded studies having large proportions (>10%) of children and pregnant women. Two authors independently carried out screening of articles, data extraction and quality assessment. Meta-analyses were done using random effects model. Meta-median difference (MMD) and 95% confidence interval (CI) was calculated for each laboratory parameter. Forty-five studies in 6 countries were included. Compared to non-severe COVID-19 cases, severe or critical COVID-19 was characterised by higher neutrophil count (MMD: 1.23 [95% CI: 0.58 to 1.88] ×10 9 cells/L), and lower lymphocyte, CD4 and CD8 T cell counts with MMD (95% CI) of -0.39 (-0.47, -0.31) ×10 9 cells/L, -204.9 (-302.6, -107.1) cells/μl and -123.6 (-170.6, -76.6) cells/μl, respectively. Other notable results were observed for C-reactive protein (MMD: 36.97 [95% CI: 27.58, 46.35] mg/L), interleukin-6 (MMD: 17.37 [95% CI: 4.74, 30.00] pg/ml), Troponin I (MMD: 0.01 [0.00, 0.02] ng/ml), and D-dimer (MMD: 0.65 [0.45, 0.85] mg/ml). Conclusions Relative to non-severe COVID-19, severe or critical COVID-19 is characterised by increased markers of innate immune response, decreased markers of adaptive immune response, and increased markers of tissue damage and major organ failure. These markers could be used to recognise severe or critical disease and to monitor clinical course of COVID-19.
【초록키워드】 COVID-19, coronavirus disease, Coronavirus disease 2019, innate immune response, children, severity, neutrophil, interleukin-6, C-reactive protein, D-dimer, troponin, CD4, database, observational studies, observational study, Laboratory, databases, pregnant women, lymphocyte, T cell, Clinical course, interleukin, predictor, troponin I, Adaptive immune response, Other, Critical, Critical disease, marker, meta-analyses, CD8 T cell, COVID-19 cases, Organ failure, systematic reviews, clinical laboratory, Google Scholar, confirmed case, Web of Science, 95% CI, tissue damage, 95% confidence interval, confirmed cases, dimer, cell counts, CINAHL, data extraction, neutrophil count, relative, random effect, MONITOR, parameter, country, articles, laboratory parameter, MMD, carried, proportion, reported, conducted, calculated, excluded, notable, eligible, 【제목키워드】 Meta-analysis, systematic review, novel coronavirus disease, Critical, clinical laboratory, parameter,