[Evaluation of the diagnostic test for rapid detection of covid-19 antigen (Panbio Covid rapid test) in primary care]. / Evaluación de la prueba diagnóstica de detección rápida de antígeno de covid-19 (Panbio Covid rapid test) en atención primaria.

OBJECTIVE: COVID-19 infection requires early diagnosis, with PCR being the gold standard test. The protocols advocate the use of rapid antigenic tests that require evaluation in actual clinical practice. The objective was to evaluate the diagnostic test for rapid antigen detection, Panbio Covid rapid test, compared with PCR, in patients with symptoms of 5 or less days of evolution and with a high-suspicion of infection by COVID-19 in a health center. MATERIALS AND METHODS: 103 patients over 14 years of age who attended an urban health center located in the Usera District of Madrid, with high-suspicion of COVID-19 infection, in the first 5 days of evolution from the onset of symptoms during the month of November 2020. INTERVENTIONS: diagnostic tests for COVID-19 are performed: antigen and PCR. RESULTS: The prevalence of the disease was 24.3% according to the PCR test and 17.5% according to the rapid antigenic test. The sensitivity was 72% (95% CI: 54.3-89.6%). The specificity was 100%. The positive and negative predictive values were 100% and 91.8% respectively. In the bivariate analysis, there was no relationship between symptoms and the presence of disease, except for myalgias (p=0.030). The multivariate analysis found a relationship between cough, dyspnea, fever, myalgia, anosmia/ageusia, and ocular symptoms and the presence of disease. CONCLUSIONS: The sensitivity and specificity for the Panbio rapid antigen test are similar to other studies performed in primary care. In high-prevalence of disease and with highly suspected symptoms, positive test results can be considered definitive, but negative results will require confirmation. Myalgia, fever, dyspnea, anosmia/ageusia, and ocular symptoms may be more related to the presence of COVID-19.

Detection of dengue viral RNA by microplate hybridization.

Dengue virus infection is a major public health problem throughout tropical countries. In endemic areas, dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) are common complications resulting in death. However, serological confirmation of dengue-related illness is often complicated and time-consuming. Detection of dengue viruses in clinical or field samples usually depends on virus isolation in susceptible cell lines or in mosquitoes, followed by viral protein identification using polyclonal or monoclonal antibodies. The increasing incidence of dengue virus infections has prompted increased efforts to develop rapid and reliable diagnostic techniques. A simple microplate hybridization method was developed for identification of viral RNA. Microplate hybridization is simpler than enzyme-linked immunosorbent assay and has several advantages over the conventional dot-blot hybridization method: (1) radioisotopes are not necessary; (2) synthetic oligonucleotide for the probe is not needed; (3) the time required for washing of the solid phase is greatly reduced; and (4) baking is eliminated. The results show that this procedure is sensitive, rapid and easy to perform.