Lymphocytes, Mean Platelet Volume, and Albumin in Critically Ill COVID-19 Patients with Venous Thromboembolism.

As one of the frequent complications leading to poor prognosis in hospitalized COVID-19 patients, a better understanding of venous thromboembolism (VTE) in COVID-19 patients is needed. We conducted a single-center, retrospective study on 96 COVID-19 patients admitted to the intensive care unit (ICU) from April to June 2022, in Shanghai Renji Hospital. Records of these COVID-19 patients upon admission were reviewed for demographic information, co-morbidities, vaccinations, treatment, and laboratory tests. VTE occurred in 11 (11.5%) cases among 96 COVID-19 patients despite the standard thromboprophylaxis since ICU admission. In COVID-VTE patients, a significant increase in B cells and a decrease in Ts cells were observed and a strong negative correlation (r = -0.9524, P = .0003) was found between these two populations. In COVID-19 patients with VTE, increased MPV and decreased albumin levels were seen in addition to the common VTE indicators of D-dimer abnormalities. The altered lymphocyte composition in COVID-VTE patients is noteworthy. In addition to D-dimer, MPV and albumin levels might be novel indicators for the risk of VTE in COVID-19 patients.

The Role of Mean Platelet Volume in Multisystem Inflammatory Syndrome in Children With Cardiac Manifestations.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a novel pediatric disorder associated with coronavirus disease 2019. However, no laboratory parameters can diagnose MIS-C. This study aimed to determine the changes in mean platelet volume (MPV) and investigate its relationship with cardiac involvement in MIS-C. METHODS: In this single-center retrospective study, 35 children with MIS-C, 35 healthy children and 35 febrile children were enrolled. Patients with MIS-C were further subdivided depending on the presence of cardiac involvement. For all patients, the white blood cell, absolute neutrophil, absolute lymphocyte, platelet counts, MPV and C-reactive protein levels were recorded. Ferritin, D-dimer, troponin and CK-MB levels and the day when IVIG was administered were recorded and compared between groups. RESULTS: Thirteen patients with MIS-C had cardiac involvement. The mean MPV of the MIS-C group was significantly higher than those of the healthy ( P = 0.0001) and febrile ( P = 0.027) groups. Using a cutoff of >7.6 fL, the MPV had a sensitivity of 82.86% and specificity of 82.75%, and the area under the MPV receiver operating characteristics curve was 0.896 (0.799-0.956). The MPV was significantly higher in patients with cardiac involvement than in those without ( P = 0.031). Logistic regression analysis revealed that the association between the MPV and cardiac involvement was significant (odds ratio, 2.28; 95% confidence interval, 1.04-2.95; P = 0 .039). CONCLUSIONS: The MPV may indicate cardiac involvement in patients with MIS-C. Large cohort studies are needed to define an accurate cutoff value for the MPV.

The effect of thrombosis-related laboratory values on mortality in COVID-19 infection.

OBJECTIVE: COVID-19 may cause thrombosis in both venous and arterial systems. Familiarity with the signs and symptoms of thrombosis and its treatment is essential in treating COVID-19 infection and its complications. D-Dimer and mean platelet volume (MPV) are measurements related to the development of thrombosis. This study investigates whether MPV and D-Dimer values could be used to determine the risk of thrombosis and mortality in the COVID-19 early stages. PATIENTS AND METHODS: 424 patients who were COVID-19 positive, according to the World Health Organization (WHO) guidelines, were randomly and retrospectively included in the study. Demographic and clinical characteristics such as age, gender, and length of hospitalization were obtained from the digital records of participants. Participants were divided into living and deceased groups. The patients' biochemical, hormonal, and hematological parameters were analyzed retrospectively. RESULTS: White blood cells (WBC), neutrophils, and monocytes were significantly different in the two groups (p-value <0.001), and their values were lower in the living group than in the deceased group. MPV median values did not differ according to prognosis (p-value = 0.994). While the median value was 9.9 in the survivors, it was 10 in the deceased. Creatinine, procalcitonin, ferritin, and the number of hospitalization days in living patients were significantly lower than in patients who died (p-value <0.001). Median values of D-dimer (mg/L) differ according to prognosis (p-value <0.001). While the median value was 0.63 in the survivors, it was found as 438 in the deceased. CONCLUSIONS: Our results did not show any significant relationship between the mortality of COVID-19 patients and their MPV levels. However, a significant association between D-Dimer and mortality in COVID-19 patients was observed.

Evaluation of inflammatory and hematological parameters in patients diagnosed with COVID-19.

INTRODUCTION: This study aims to research the effects of hematological and inflammatory parameters on the prognosis of COVID-19 disease and hospitalization duration. METHODOLOGY: One hundred and eighty-six patients with COVID-19 and a control group consisting of 187 healthy individuals were included in the study. Hematological variables and inflammatory parameters of the patients were recorded on the first and the fifth days of hospitalization. RESULTS: White blood cell count, lymphocyte count, and platelet count were statistically lower, and mean platelet volume (MPV), neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR) levels were higher in the patient group compared to the control group. It was observed that the neutrophil count and MPV level were lower, and the platelet count and ferritin level were statistically higher on the fifth day of follow-up compared to the admission day. In contrast, there was a significantly positive correlation between the duration of hospitalization and the fifth day D-dimer (r = 0.546, p < 0.001) and ferritin (r = 0.568, p < 0.001); in addition, there was a negative correlation between the duration of hospitalization and admission day lymphocyte count and the fifth-day lymphocyte count. CONCLUSIONS: Increased levels of ferritin and D-dimer, and decreased count of lymphocytes are among the important factors affecting the duration of hospitalization for COVID-19 patients. Furthermore, we think that neutrophil count and MPV levels are low, and platelet count and ferritin levels are high during the disease. Therefore, these parameters can be used as prognostic indicators of the disease.

A mean platelet volume in inflammatory bowel disease: A systematic review and meta-analysis.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic gastrointestinal tract inflammatory state, which is affecting millions of individuals in the world. It can affect alimentary canals such as colon, rectum, ileum and other parts. In IBD, platelet parameters underwent several changes. Therefore, the aim of this review was determining the estimated pooled mean platelet volume and mean difference in inflammatory bowel disease to elucidate its potential diagnostic value. METHODS: Articles were extensively searched in bibliographic databases using Medical Subject Heading and entry phrases or terms. In addition, articles were directly searched in Google Scholar to account for the studies omission in searching bibliographic databases. Observational (cohort, cross-sectional and case-control) studies, published in English language and conducted on IBD were included. For studies meeting the eligibility criteria, the first author's name, publication year, population, study design, study area, sample size, mean platelet volume and standard deviation were extracted and entered in to Microsoft-excel. The analysis was done by Stata version 11. In order to estimate the pooled mean platelet volume and mean difference, random effect model was done. The heterogeneity was quantified using Higgin's I2 statistics. Publication bias was determined using Egger's test statistics and funnel plot. Sub-group analysis based on population carried to reduce heterogeneity. RESULTS: A total of 17 relevant articles with 2957 participants (1823 IBD cases and 1134 healthy controls) were included to this study. The pooled estimated MPV was 9.29fl; 95% CI: 9.01-9.57 and 9.50fl; 95% CI: 8.81-10.20 in IBD and control groups, respectively. The standardized pooled estimate of mean difference in mean platelet volume was -0.83fl; 95% CI: -1.15, -0.51; I2: 93.1%; P-value < 0.001. In subgroup analysis based on population, the highest estimated mean difference in MPV was observed among patients of CD; -2.30; 95% CI: -3.46, -1.14; I2: 97.8%; P-value < 0.001. CONCLUSION: According to the current systematic review and meta-analysis, mean platelet volume was lower in IBD compared to control. The decreased mean platelet volume could be attributed to platelet consumption or sequestration associated with the progression of IBD. As a result, in IBD, mean platelet volume can provide diagnostic and prognostic information.

Platelet Indices Are the Promising Biomarkers in Monitoring Disease Activities in Patients with Syphilis.

OBJECTIVES: To uncover the role of the platelet indices in patients with syphilis. METHODS: A total of 2061 patients with syphilis and 528 healthy controls were enrolled in this retrospective cohort study. The data of platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and indicators of syphilis activities were collected. The correlations between the platelet indices and disease activities were analyzed. RESULTS: A total of 425 (20.6%) of the 2061 patients were of primary and secondary syphilis, 433 (21.0%) latent, 463 (22.5%) serofast, 350 (17.0%) asymptomatic neurosyphilis, and 390 (18.9%) symptomatic neurosyphilis. Compared with the healthy controls, PLT was significantly increased in the primary and secondary syphilis group; whereas, MPV and PDW were significantly decreased in all stages of syphilis. These changes of platelet indices were reversed after anti-treponemal therapy. Further correlation analysis showed that PLT was positively associated with the syphilis activity indicators [rapid plasma reagin (RPR) titer, cerebrospinal fluid white blood cell (CSF-WBC), CSF-protein, and CSF-VDRL (venereal disease research laboratory)] and inflammatory markers [WBC, C-reaction protein (CRP), and erythrocyte sedimentation rate (ESR)]. Conversely, PDW was negatively correlated with all of these parameters. MPV had an inverse relationship with RPR, ESR, and CRP. CONCLUSIONS: Platelet indices are associated with syphilis activities.

Influence of COVID-19 on lymphocyte and platelet parameters among patients admitted to intensive care unit and emergency.

OBJECTIVE: The aim of the study was to detect the effect of COVID-19 on lymphocyte and platelet parameters among Sudanese patients admitted to Intensive Care unit (ICU) and emergency (ER). PATIENTS AND METHODS: This cross-sectional study was carried out on a total of 787 Sudanese individuals (487 confirmed COVID-19 cases and 300 apparently healthy individuals as controls, in duration between April 2020 to December 2020). Platelets (PLTs) and platelet indices, mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT) and platelet larger cell ratio (PLCR) were investigated as part of the complete blood count (CBC) for the case and control group. Also, the neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) were calculated, and the results were statistically analyzed by SPSS version 21. RESULTS: The severity of the disease was also affected by the patient's age: 262 COVID-19 cases admitted to ICU were over 50 years old, compared to only four patients in the mild group. Regarding hematological parameters, the absolute lymphocyte count, PLTs, MPV, PDW, and P-LCR were significantly different between cases and control groups (p-values = 0.000, 0.002, 0.000, 0.000, and 0.000, respectively). PLR and NLR levels were found to be significantly higher as disease severity increased; p-values = 0.000 and 0.000, respectively. The study also demonstrated that lymphopenia was associated with severe COVID-19 infection (in 93% of ICU patients, 59.9% of ER, and 9% of the mild group), while thrombocytopenia was detected only among 30.8% of ICU patients. CONCLUSIONS: Lymphopenia and thrombocytopenia are associated with severe COVID-19 infection. NLR and PLR were markedly increased with COVID-19.

Relationship of platelet counts, platelet volumes, and Curb-65 scores in the prognosis of COVID-19 patients.

OBJECTIVES: This study investigated the relationship between 28-day mortality in patients with COVID-19 pneumonia and the CURB-65 score, platelet count (PLT), mean platelet volume (MPV), and MPV/PLT ratio (MPR). METHODS: A total of 247 patients with COVID-19 pneumonia who presented to the emergency department between March 15, 2020 and May 15, 2020 were retrospectively analyzed. The age, gender, clinical presentation, history of chronic disease, thoracic computed tomography findings, MPV, PLT, MPR, CURB-65 scores, and 28-day mortality of patients were recorded. RESULTS: The patients had a mean age of 51 years (IQR: 39-63 years) and 55.5% were females. The most common symptom was cough (30.4% of patients). The most common comorbidity was hypertension (13.4%), 49.8% of the cases showed intermediate involvement, and 7.7% of patients died within the first 28 days. The mean MPV was 9.71 ± 1.15, the mean PLT was 226.68 ± 83.82, and the mean MPR was 0.056 ± 0.12. There were significant correlations of 28-day mortality with the CURB-65 score, MPV, and MPR levels (p = 0.000, p = 0.034, and p = 0.034, respectively). No significant correlation was found between the PLT count and 28-day mortality (p = 0.105). CONCLUSIONS: In addition to the CURB-65 score, MPV and MPR values can be used to predict 28-day mortality in patients with COVID-19 pneumonia.

Significance of MPV, RDW and PDW with the Severity and Mortality of COVID-19 and Effects of Acetylsalicylic Acid Use.

We aimed to investigate association between mean platelet volume (MVP), platelet distribution width (PDW) and red cell distribution width (RDW) and mortality in patients with COVID-19 and find out in which patients the use of acetylsalicylic acid (ASA) affects the prognosis due to the effect of MPV on thromboxan A2. A total of 5142 patients were divided into those followed in the intensive care unit (ICU) and those followed in the ward. Patient medical records were examined retrospectively. ROC analysis showed that the area under curve (AUC) values were 0.714, 0.750, 0.843 for MPV, RDW and D-Dimer, the cutoff value was 10.45fl, 43.65fl, 500.2 ng/mL respectively. (all P < .001). Survival analysis showed that patients with MPV >10.45 f/l and D-Dimer >500.2 ng/mL, treatment with ASA had lower in-hospital and 180-day mortality than patients without ASA in ICU patients (HR = 0.773; 95% CI = 0.595-0.992; P = .048, HR = 0.763; 95% CI = 0.590-0.987; P = .036). Administration of low-dose ASA in addition to anti-coagulant according to MPV and D-dimer levels reduces mortality.

COVID-19 in Pregnancy: Implication on Platelets and Blood Indices.

OBJECTIVE: To describe the hematological changes, the platelet indices in particular, in pregnant women with coronavirus disease 2019 (COVID-19) compared to healthy pregnant women. METHODS: A retrospective case-control study conducted at the Al Yarmouk Teaching Hospital, in Baghdad, Iraq, involving 100 pregnant women, 50 with positive viral DNA for COVID-19 (case group), and 50 with negative results (control group); both groups were subjected to a thorough hematological evaluation. RESULTS: Among the main hematological variables analyzed, the platelet indices, namely the mean platelet volume (MPV) and the platelet distribution width (PDW), showed statistically significant differences (MPV: 10.87 ± 66.92 fL for the case group versus 9.84 ± 1.2 fL for the control group; PDW: 14.82 ± 3.18 fL for the case group versus 13.3 ± 2.16 fL for the controls). The criterion value of the receiver operating characteristic (ROC) curve for PDW at a cutoff point of > 11.8 fL showed a weak diagnostic marker, while the MPV at a cutoff value of > 10.17 fL showed a good diagnostic marker. CONCLUSION: The MPV and PDW are significantly affected by the this viral infection, even in asymptomatic confirmed cases, and we recommend that both parameters be included in the diagnostic panel of this infection.

OBJETIVO: Descrever as alterações hematológicas, em particular os índices plaquetários em gestantes com doença coronavírus 2019 (COVID-19) em comparação com gestantes saudáveis. MéTODOS: Estudo caso-controle retrospectivo realizado no Hospital Universitário Al Yarmouk, em Bagdá, Iraque envolvendo 100 gestantes, 50 com DNA viral positivo para COVID-19 (grupo caso) e 50 com resultados negativos (grupo controle); ambos os grupos foram submetidos a uma avaliação hematológica completa. RESULTADOS: Entre as principais variáveis hematológicas analisadas, os índices plaquetários, nomeadamente o volume plaquetário médio (VPM) e a largura de distribuição plaquetária (PDW), apresentaram diferenças estatisticamente significativas (VPM: 10,87 ± 66,92 fL para o grupo caso versus 9,84 ± 1.2 fL para o o grupo controle; PDW: 14,82 ± 3,18 fL para o grupo caso versus 13,3 ± 2,16 fL para os controles). O valor de critério da curva de característica de operação do receptor (ROC) para PDW em um ponto de corte de> 11,8 fL mostrou um marcador diagnóstico fraco, enquanto o do VPM em um valor de corte de> 10,17 fL mostrou um bom marcador de diagnóstico. CONCLUSãO: O MPV e PDW são significativamente afetados por esta infecção viral, mesmo em casos confirmados assintomáticos, e recomendamos que ambos os parâmetros sejam incluídos no painel de diagnóstico desta infecção.

High immature platelet fraction with reduced platelet count on hospital admission. Can it be useful for COVID-19 diagnosis?

INTRODUCTION: Health professions are heavily engaged facing the current threat of SARS-CoV-2 (COVID-19). Although there are many diagnostic tools, an accurate and rapid laboratory procedure for diagnosing COVID-19 is recommended. We focused on platelet parameters as the additional biomarkers for clinical diagnosis in patients presenting to the emergency department (ED). MATERIALS AND METHODS: Five hundred and sixty-one patients from February to April 2020 have been recruited. Patients were divided into three groups: (N = 50) COVID-19 positive and (N = 21) COVID-19 negative with molecular testing, (N = 490) as reference population without molecular testing. A Multiplex rRT-PCR from samples collected by nasopharyngeal swabs was performed and the hematological data collected. RESULTS: We detected a mild anemia in COVID-19 group and lymphopenia against reference population: hemoglobin (g/dL) 13.0 (11.5-14.8) versus 13.9 (12.8-15.0) (P = .0135); lymphocytes (109 /L) 1.24 (0.94-1.73) versus 1.99 (1.49-2.64) (P < .0001). In addition, abnormal platelet parameters as follows (COVID group vs reference population): PLT (×109 /L) 209 (160-258) vs 236 (193-279) (P = .0239). IPF (%) 4.05 (2.5-5.9) versus 3.4 (2.2-4.9) (P = .0576); H-IPF (%) 1.25 (0.8-2.2) versus 0.95 (0.6-1.5) (P = .0171) were identified. In particular, COVID positive group had a high H-IPF/IPF Ratio compared to reference population [0.32 (0.29-0.36) versus 0.29 (0.26-0.32), respectively, (P = .0003)]. Finally, a PLT difference of nearly 50 × 109 /L between pre/postCOVID-19 sampling for each patient was found (N = 42) (P = .0194). CONCLUSIONS: COVID-19 group results highlighted higher IPF and H-IPF values, with increased H-IPF/IPF Ratio, associated to PLT count reduction. These findings shall be adopted for a timely diagnosis of patients upon hospital admission.

EVALUATION OF THE RELATIONSHIP OF MPV, RDW AND PVI PARAMETERS WITH DISEASE SEVERITY IN COVID-19 PATIENTS.

Coronavirus was first detected in three severe pneumonia cases in Wuhan, China, in December 2019. Studies on red cell distribution width (RDW-CV) and mean platelet volume (MPV) laboratory parameters, which can be examined in complete blood count in COVID-19 patients, are still very limited. However, to the best of our knowledge, there are no studies examining the relationship between platelet volume index (PVI) and disease severity in COVID-19 patients, which was evaluated in this study. The aim of this study was to evaluate the relationship of disease severity in COVID-19 patients with their MPV, RDW, and PVI parameters. The study included 92 COVID-19 patients as a study group and 84 healthy individuals as control group. All laboratory data and radiological images were scanned retrospectively from patient files and hospital information system. Evaluation of the RDW-CV and MPV blood parameters, and PVI measured in COVID-19 patients yielded statistically significant differences according to the disease severity. We suggest that RDW-CV and PVI, evaluated within the scope of the study, may be the parameters that should be considered in the early diagnosis of the disease, from the initial stages of COVID-19. In addition, we think that the RDW-CV and MPV laboratory parameters, as well as PVI, which all are simple, inexpensive and widely used hematologic tests, can be used as important biomarkers in determining COVID-19 severity and mortality.

[Expressions of MPV, P-LCR and NLR in patients with novel coronavirus disease 2019].

To provide new ideas for clinical diagnosis and treatment of coronavirus disease 2019 (COVID-19), this study explore the expression level and prognostic value of platelet parameters in mild, moderate and severe COVID-19. This is a retrospective analysis. From January to May 2020, a total of 69 patients who were diagnosed with COVID-19 in the Third Central Hospital and the Jinnan Hospital (both situated in Tianjin) were enrolled in the disease group. According to the severity, these patients were divided into mild group (15 cases), moderate group (46 cases), and severe group (8 cases). In the same period, 70 non-infected patients were enrolled in control group. The level of white blood cell count (WBC), absolute neutrophil count (NEU#), absolute lymphocyte count (LY#), neutrophil-lymphocyte ratio (NLR), red blood cell count (RBC), hemoglobin (Hb), platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large contrast ratio (P-LCR) before and after treatment were analyzed. Binary logistic regression analysis is used to establish a mathematical model of the relationship between these indexes and the outcome of severe COVID-19 patients. The receiver operating characteristic(ROC) curve is used to further explore the prognosis value of MPV, P-LCR, NLR separately and jointly in COVID-19 patients. Compare to the control group, WBC and NE# increase (Z=-5.63, P<0.01;Z=-9.19,P<0.01) and LY# decrease (Z=-9.34, P<0.01) in the severe group; NLR increase with the aggravation of the disease, there is significant difference between groups (Z=17.61, P<0.01); PLT, PDW, MPV and P-LCR decrease with the aggravation of the disease, there is significant difference between groups (Z=9.47, P<0.01; Z=11.41, P<0.01; Z =16.76, P<0.01; Z=13.97, P<0.01). Binary logistic regression analysis shows MPV, P-LCR and NLR have predictive value for severe COVID-19 patients. There is a negative correlation between MPV, P-LCR and severe COVID-19 patients (OR=1.004, P=0.034; OR=1.097, P=0.046). There is a positive correlation between NLR and severe COVID-19 patients (OR=1.052, P=0.016). MPV and P-LCR of patients with good prognosis after treatment were significantly higher than those before treatment (Z=-6.47, P<0.01; Z=-5.36, P<0.01). NLR was significantly lower than that before treatment (Z=-8.13, P<0.01). MPV and P-LCR in poor prognosis group were significantly lower than those before treatment (Z=-9.46, P<0.01; Z=-6.81, P<0.01). NLR was significantly higher than that before treatment (Z=-3.24, P<0.01). There were significant differences between good and poor prognosis groups before and after treatment in MPV, P-LCR and NLR (P<0.01). Combination of these three indexes, ROC shows the AUC is 0.931, the sensitivity is 91.5%, the specificity is 94.1%, the positive predictive value is 88.9%, and the negative predictive value is 87.4%, which is better than any of these indexes separately. Changes in these parameters are closely related to clinical stage of COVID-19 patients. MPV, P-LCR and NLR are of great value in the prediction and prognosis of severe COVID-19 patients.

Platelet Indices' Usefulness in Determining whether Patients with COVID-19 Should be Treated as an Outpatient or Inpatient: a Retrospective Study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has affected the health system around the world. It is necessary to facilitate health care services with useful parameters in patient follow-up. In this study, we wanted to determine whether platelet indices can be used as an assistant parameter in the clinician's decision-making process regarding which of the patients diagnosed with COVID-19 should be treated by hospitalization. METHODS: This retrospective study was performed in a secondary care hospital in Mugla, Turkey. Demographic information such as age, gender, and comorbidities of patients admitted to the emergency pandemic outpatient clinic within five months and diagnosed with COVID-19, as well as discharge, hospitalization, or intensive care needs (ICU), and thirty-day mortality were noted. Also, patients with platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), thrombocytocrit (PCT), MPV/PLT, MPV/PCT, PDW/PLT, PDW/PCT values for outpatient follow-up, hospitalization, intensive care unit need, and 30-day mortality relationships were examined. RESULTS: A total of 93 patients diagnosed with COVID-19 were included in the study. It was observed that those with comorbidity had a statistically significant higher rate of hospitalization (p = 0.013). No statistically significant difference was found between outpatients and inpatients in terms of PLT, MPV, PDW, PCT, MPV/PLT, MPV/ PCT, PDW/PLT, and PDW/PCT (p > 0.05 for each). CONCLUSIONS: Platelet indices such as PLT, MPV, PDW, PCT, MPV/PLT, MPV/PCT, PDW/PLT, and PDW/PCT are not useful parameters for the clinician to distinguish between outpatient and inpatient treatment of patients with COVID-19.

Lymphocyte/mean platelet volume ratio, a new marker; is it effective in predicting the prognosis of COVID-19 cases?

OBJECTIVES: This study aims to determine the prognostic significance of the lymphocyte/mean platelet volume ratio (LMR) in terms of the clinical course of the disease in patients with COVID-19. METHODS: Patients over 18 who were evaluated for COVID-19 during the period from April 1, to April 30, 2020 were retrospectively scanned. Patients with at least 1 positive PCR test result were as assigned to Group 1 while patients with negative test results were assigned to Group 2. The LMR ratio was calculated by dividing the lymphocyte value by that of MPV. The relationship between LMR, severity of patients' CT findings and 28-day mortality was evaluated. RESULTS: A total of 938 patients were included in the study. It was observed that the lymphocyte and LMR levels were significantly different in those who died within 28 days (p < 0.001, p ≤ 0.001). In the ROC analysis for the LMR level, the area under the curve (AUC) was found to be 0.737 (95% CI 0.639‒0.834). When the cut­off value of LMR was 0.045, the sensitivity was found to be 99.0 % and specificity was 15.2 %. CONCLUSION: LMR can be a guide in multiple cases of care provided to critical patients, as is the case in the COVID-19 pandemic and can be used in recognizing critical patients (Tab. 5, Fig. 1, Ref. 21).