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BackgroundReal-time reverse transcription polymerase chain reaction (RT-qPCR) is the current recommended laboratory method to diagnose SARS-CoV-2 acute infection, several factors such as requirement of special equipment, time consuming, high cost and skilled staff limit the use of these molecular techniques. A more rapid and high-throughput method is in growing demand.MethodsEvaluate the performances of the Panbio™ COVID-19 AG Rapid Test Device (Nasopharyngeal), a rapid immunochromatographic test for the detection of SARS-CoV-2 antigen, in comparison to RT-qPCR.ResultsThe RDT evaluated in this study showed a high sensitivity and specificity in samples mainly obtained during the first week of symptoms and with high viral loads.ConclusionsThis assay seems to be an effective strategy for controlling the COVID-19 pandemic for the rapid identification and isolation of SARS-CoV-2 infected patients.

Objectives:Serologic techniques can serve as a complement to diagnose SARS-CoV-2 infection. The objective of our study was to compare the diagnostic performance of six immunoassays to detect antibodies against SARS-CoV-2: three lateral flow immunoassays (LFAs), one ELISA and two chemiluminescence assays (CLIAs).Methods:We evaluated three LFAs (Alltest, One Step and SeroFlash), one ELISA (Dia.Pro) and 34 two CLIAs (Elecsys and COV2T). To assess the specificity, 60 pre-pandemic sera were 35 used. To evaluate the sensitivity, we used 80 serum samples from patients with 36 positive PCR for SARS-CoV-2. Agreement between techniques was evaluated using the kappa score (k).ResultsAll immunoassays showed a specificity of 100% except for SeroFlash (96.7%). Overall sensitivity was 61.3%, 73.8%, 67.5%, 85.9%, 88.0% and 92.0% for Alltest, One Step, SeroFlash, Dia.Pro, Elecsys and COV2T, respectively. Sensitivity increased throughout the first two weeks from the onset of symptoms, reaching sensitivities over 85% from 14 days for all LFAs, being One Step the most sensitive (97.6%), followed by SeroFlash (95.1%). Dia.Pro, Elecsys and COV2T showed sensitivities over 97% from 14 days, being 100% for COV2T. One Step showed the best agreement results among LFAs, showing excellent agreement with Dia.Pro (agreement=94.2%, k=0.884), COV2T (99.1%, k=0.981) and Elecsys (97.3%, k=0.943). Dia.Pro, COV2T and Elecsys also showed excellent agreement between them.ConclusionOne Step, Dia.Pro, Elecsys and COV2T obtained the best diagnostic performanc e results. All these techniques showed a specificity of 100% and sensitivities over 97% from 14 days after the onset of symptoms, as well as excellent levels of agreement.

BACKGROUNDThe coronavius disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reached Spain by 31 January 2020, in April 2020, the Comunidad de Madrid suffered one of the world’s highest crude mortality rate ratios. This study aimed to detect risk factors for mortality in patients with COVID-19.METHODSOur cohort were all consecutive adult patients (≥18 years) with laboratory-confirmed COVID-19 at a secondary hospital in Madrid, March 3-16, 2020. Clinical and laboratory data came from electronic clinical records and were compared between survivors and non-survivors, with outcomes followed up until April 4. Univariable and multivariable logistic regression methods allowed us to explore risk factors associated with in-hospital death.FINDINGSThe cohort comprised 562 patients with COVID-19. Clinical records were available for evaluation for 392 patients attended at the emergency department of our hospital, of whom 199 were discharged, 85 remained hospitalized and 108 died during hospitalization. Among 311 of the hospitalized patients, 34.7% died. Of the 392 patients with records, the median age was 71.5 years (50.6-80.7); 52.6% were men. 252 (64.3%) patients had a comorbidity, hypertension being the most common: 175 (44.6%), followed by other cardiovascular disease: 102 (26.0%) and diabetes: 97 (24.7%). Multivariable regression showed increasing odds of in-hospital death associated with age over 65 (odds ratio 8.32, 95% CI 3.01–22.96; pINTERPRETATIONCOVID-19 was associated in our hospital at the peak of the pandemic with a crude mortality ratio of 19.2% and a mortality ratio of 34.7% in admitted patients, considerably above most of the ratios described in the Chinese series. These results leave open the question as to which factors, epidemiological or intrinsically viral, apart from age and comorbidities, can explain this difference in excess mortality.FUNDINGNone.

Objectives: SARS-CoV-2 infection constitutes a diagnostic challenge in patients from 2-3 weeks after the onset of symptoms, due to the low positivity rate of the PCR, especially in upper respiratory samples. Serologic tests based on ELISA have been developed and evaluated as useful complements to PCR in these situations. However, there is scarce information about the usefulness of rapid tests based on immunochromatography. The aim of our study was to analyze the diagnostic performance of these rapid tests in COVID-19 pneumonia patients. Methods: We evaluated an immunochromatographic test (AllTest COV-19 IgG / IgM kit) which detects IgG and IgM antibodies. First, we performed a validation of the serologic test using serum samples from 45 healthy control patients (group 1) and 55 confirmed by PCR cases of COVID-19 (group 2) in order to establish the specificity and sensitivity, respectively. Then we prospectively employed the test in 63 patients diagnosed with pneumonia of unknown etiology that were SARS-CoV-2 negative by PCR (group 3), to establish the diagnostic performance in these patients. Results: All patients from group 1 (healthy controls) resulted negative for the serologic test (specificity = 100%). Regarding group 2 (PCR positive) patients, the median time from the onset of symptoms was 11 days and the test was positive for either IgM or IgG in 26 out of 55 patients (overall sensitivity = 47.3%). However, in those patients with 14 days or more from onset of symptoms, the sensitivity was 73.9%. Regarding group 3 patients, the median days from onset of symptoms was 17 and the test was positive in 56 out of 63 patients (88.9% positivity rate). In these group 3 patients with 14 days or more from onset of symptoms, the positivity rate was 91.1%. Conclusions: Our study shows that serologic rapid tests can be used as a complement of PCR to diagnose SARS-CoV-2 infection after 14 days from the onset of symptoms. These immunochromatographic devices could be especially useful in hospitalized patients with pneumonia of unknown etiology with 14 or more days from the onset of symptoms and in whom the PCR has been negative.