key: cord-0822165-s3nb11je authors: Osman, Jennifer; Lambert, Jérome; Templé, Marie; Devaux, Floriane; Favre, Rémy; Flaujac, Claire; Bridoux, Delphine; Marque‐Juillet, Stéphanie; Bruneel, Fabrice; Mignon, François; Diaz‐Flores, Ernesto; Hentgen, Véronique; Greder‐Belan, Alix; Azarian, Reza; Koukabi, Mehrsa; Rousselot, Philippe; Raggueneau, Victoria; Manéglier, Benjamin title: Rapid screening of COVID‐19 patients by White blood cells scattergrams, a study on 381 patients date: 2020-06-15 journal: Br J Haematol DOI: 10.1111/bjh.16943 sha: 15e17eaaabe3752e8d63a78c9af5ba2bbe259117 doc_id: 822165 cord_uid: s3nb11je Complementary tools are warranted to increase the sensitivity of the initial testing for COVID‐19. We identified a specific “sandglass” aspect on the white blood cells scattergram of COVID‐19 patients reflecting the presence of circulating plasmacytoid lymphocytes. Patients were dichotomized as COVID‐19 positive or negative based on RT‐PCR and chest CT scan results. Sensitivity and specificity of the “sandglass” aspect were 85.9% and 83.5% respectively. The positive predictive value was 94.3%. Our findings provide a non‐invasive and simple tool to quickly categorize symptomatic patients as either COVID‐19 probable or improbable especially when RT‐PCR and/or chest CT are not rapidly available. The novel coronavirus SARS-CoV-2, responsible for COVID-19 confronts the health community with major challenges.(1) Early diagnosis of COVID-19 is crucial for the optimal management of infected patients to control viral spread. The standard test for COVID-19 remains the Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) to detect viral RNA from clinical samples. RT-PCR is specific but lacks sensitivity. (2) (3) (4) Complementary tools are warranted to increase the sensitivity of the initial testing of COVID-19 patients. Complete blood count (CBC) is a routine test during initial biological assessment of patients. CBC analyzers such as SYSMEX ® (Japan), provide a white blood cells (WBC) differential fluorescence (WDF) scattergram, displaying a classification of WBC based on their morphology and their intracellular components. Each type of leucocyte is always displayed on the same area. The different clusters of leucocytes displayed on the WDF match with the visual examination by optical microscopy. During this outbreak, we have noticed a recurrent atypical aspect on the WDF of COVID-19 patients. We therefore decided to evaluate the sensitivity and specificity of our finding in order to propose WDF as a screening tool for COVID-19. Patients admitted at Versailles Hospital suspected of having COVID-19 were eligible if symptoms were present for 3 or more days and if RT-PCR and a chest CT were performed (Supplementary This article is protected by copyright. All rights reserved Chest CT scans were performed on GENERAL ELECTRIC ® scanners (USA) and classified as typical (CT + ) or not (CT -) for COVID-19 according to published definition. (3, (5) (6) (7) "Index test" was the WDF pattern on the CBC performed at admission time, whereas the "reference test" was a diagnostic algorithm combining RT-PCR and CT results, as recommended by recent studies. (3, 5) We excluded patients with symptoms for less than 3 days to overcome the "grey-zone" of the chest CT. Patients with at least one RT-PCR + and/or CT + were considered as COVID-19 positive (COVID-19 + ) whereas patients with RT-PCRand CTwere considered as COVID-19 negative (COVID-19 -). WDF and Chest CT interpretations were blinded. Once dichotomized (COVID-19 + / -), diagnostic performances of WDF were calculated. All statistical analyses were performed using R version 3.6.1 (R Core Team 2019 We noticed a recurrent atypical aspect on the WDF scattergram of COVID-19 patients. This aspect, named the "sandglass" pattern, consisted of a discontinuous cluster of lymphocytes characterized by the presence of more than 4 dots in the upper graduation of the scattergram, where plasmacytoid lymphocytes are usually plotted (8, 9) . This observation was reinforced by the presence of circulating plasmacytoid lymphocytes on blood smears from patients with COVID-19 whereas large hyperbasophilic lymphocytes, normally seen in other viral infections, were absent Complete characteristics of patients are reported in Table 1 . In summary, 57% (216/381) of the patients were hospitalized including 36 patients (9%) immediately admitted to the intensive care unit for an acute respiratory distress syndrome. Loss of This article is protected by copyright. All rights reserved smell/taste (33/290) and lymphopenia (159/290) were largely reported in COVID-19 + patients versus COVID-19 -. (7, (11) (12) (13) The COVID-19 status confirmation was available within 1 day for 353/381 (93%) patients (range: 0-3 days). Of the 381 patients studied 290 (76%) were COVID-19 + and 91 (24%) were COVID-19 -. Among COVID-19 + patients, 247 (85%) had RT-PCR + /CT + , 35 (12%) had RT-PCR -/CT + and 8 (3%) had RT-PCR + /CT -. Interestingly, 25 COVID-19 + patients with WDFhad a further CBC available, and the WDF We report here a specific and original "sandglass" aspect on the WDF scattergram of COVID-19 patients. We hypothesize that this pattern reflects the presence of circulating plasmacytoid lymphocytes as observed from our careful blood smears examination of COVID-19 patients (8, 9) . Circulating plasmacytoid lymphocytes, absent in healthy people, have previously been reported in COVID-19 (14, 15) and deserve further immunological explorations. We showed that WDF is a highly reliable screening test to detect COVID-19 patients with 85.9% sensitivity and 83.5% specificity. It remains a simple, rapid, inexpensive, and non-invasive method. Due to COVID-19 associated lymphopenia, (7, 11, 12 ) WDF analysis appears more accurate than blood smear examination. If confirmed, detection of circulating plasmacytoid lymphocytes can be a useful alternative for centers where WDF is not available. Our study however presents some limitations: First, it is a monocentric study carried out using a specified type of CBC analyzers. However, SYSMEX ® analyzers are largely available in clinical institutions all over the world. This report may allow other laboratories and hospitals to confirm our results and provide multicentric data. Second, in order to exclude undetermined cases and reduce potentially wrong dichotomization resulting from early negative CT,(5-7) we excluded early symptomatic patients. Thus, prevalence of COVID-19 cases was higher than in the general population for which RT-PCR was required, and therefore PPV may be overestimated while NPV underestimated. Based on this retrospective study, we conclude that WDF analysis can be implemented during the SARS-CoV-2 pandemic to quickly categorize symptomatic patients as either COVID-19 probable or improbable, depending on the presence of the plasmacytoid lymphocytes cluster on their scattergram. Finally, given that CBC is available within few minutes, the "sandglass" WDF pattern may be a valuable tool assisting clinicians to pilot the medical management of symptomatic patients suspected of having COVID-19 at time of admission in hospitals. This simple tool may be of particular importance (i) when RT-PCR and/or chest CT are not rapidly available, (ii) to decide to repeat the RT-PCR, (iii) in addition to other diagnostic tools such as chest CT and (iv) for patients for whom the diagnosis was not initially suspected. We are now conducting a prospective validation cohort to derive a new algorithm combining RT-PCR, chest CT and WDF in order to facilitate the initial management of symptomatic patients suspected of having COVID-19. Accepted Article COVID-19) outbreak Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases Diagnostic Performance of CT and Reverse Transcriptase-Polymerase Chain Reaction for Coronavirus Disease 2019: A Meta-Analysis Evaluating the accuracy of different respiratory specimens in the laboratory diagnosis and monitoring the viral shedding of 2019-nCoV infections. medRxiv Radiological findings from 81 patients with COVID-19 pneumonia in Wuhan, China: a descriptive study Performance of radiologists in differentiating COVID-19 from viral pneumonia on chest CT Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China Sensitivity and specificity of the high fluorescent lymphocyte count-gate on the Sysmex XE-5000 hematology analyzer for detection of peripheral plasma cells Identification and quantification of high fluorescence-stained lymphocytes as antibody synthesizing/secreting cells using the automated routine hematology analyzer XE-2100 The inconsistency of "optimal" cutpoints obtained using two criteria based on the receiver operating characteristic curve Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China Accepted Article This article is protected by copyright. All rights reserved Self-reported Olfactory and Taste Disorders in Patients With Severe Acute Respiratory Coronavirus 2 Infection: A Cross-sectional Study Plasmacytoid lymphocytes in SARS-CoV-2 infection (Covid-19) Reactive lymphocytes in patients with Covid-19