ABSTRACT
In this nested case-control study, we evaluated haematological and morphological parameters of hospitalised patients with real-time polymerase chain reaction verified COVID-19 infection compared to patients with similar symptomatology but without COVID-19 infection. Seventy-four COVID-19 positive and 228 COVID-19 negative patients were evaluated with routine haematological parameters. Severe disease was defined as death and/or need of intensive care treatment. Twenty-seven COVID-19 positive and 18 COVID-19 negative patients were furthermore included for morphological evaluation using smear examination. Significant differences were found for platelet indices and white blood cell parameters. Thus, platelet count and plateletcrit was lower in COVID-19 patients, whilst mean platelet volume, platelet distribution width, and platelet large cell ratio was significantly higher than in non-COVID-19 patients. Leukocyte, neutrophil, immature granulocyte, lymphocyte, monocyte, eosinophil, and basophil count was lower in COVID-19 patients. No significant differences were found for red blood cell count, haemoglobin, haematocrit or mean corpuscular haemoglobin for COVID-19 versus non-COVID-19 patients. COVID-19 patients with a severe disease course had higher levels of immature granulocytes, but lower lymphocyte and platelet counts compared to patients with non-severe COVID-19. In terms of morphology, 14.8% of COVID-19 patients had a normal smear examination, compared to 83.3% of non-COVID-19 patients. Hypogranulated neutrophils were more frequent in COVID-19 patients (p < .001), but non-COVID-19 patients had higher levels of reactive lymphocytes, compared to COVID-19 patients. In conclusion, several haematological morphological abnormalities are more frequent in patients with COVID-19 disease, and several findings indicate that platelets play a fundamental role in the pathophysiology of the disease.
Subject(s)
Blood Platelets/pathology , COVID-19/blood , Leukocytes/pathology , SARS-CoV-2 , Adult , Aged , Case-Control Studies , Female , Humans , Leukocyte Count , Male , Middle Aged , Platelet CountABSTRACT
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 causes coronavirus disease 2019 (COVID-19) and poses substantial challenges for healthcare systems. With a vastly expanding number of publications on COVID-19, clinicians need evidence synthesis to produce guidance for handling patients with COVID-19. In this systematic review and meta-analysis, we examine which routine laboratory tests are associated with severe COVID-19 disease. CONTENT: PubMed (Medline), Scopus, and Web of Science were searched until March 22, 2020, for studies on COVID-19. Eligible studies were original articles reporting on laboratory tests and outcome of patients with COVID-19. Data were synthesized, and we conducted random-effects meta-analysis, and determined mean difference (MD) and standard mean difference at the biomarker level for disease severity. Risk of bias and applicability concerns were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2. SUMMARY: 45 studies were included, of which 21 publications were used for the meta-analysis. Studies were heterogeneous but had low risk of bias and applicability concern in terms of patient selection and reference standard. Severe disease was associated with higher white blood cell count (MD, 1.28 ×109/L), neutrophil count (MD, 1.49 ×109/L), C-reactive protein (MD, 49.2 mg/L), lactate dehydrogenase (MD, 196 U/L), D-dimer (standardized MD, 0.58), and aspartate aminotransferase (MD, 8.5 U/L); all p < 0.001. Furthermore, low lymphocyte count (MD -0.32 × 109/L), platelet count (MD -22.4 × 109/L), and hemoglobin (MD, -4.1 g/L); all p < 0.001 were also associated with severe disease. In conclusion, several routine laboratory tests are associated with disease severity in COVID-19.