ABSTRACT
This study aimed to evaluate the performance of the PanbioTM Covid-19 Ag Rapid Test (Abbott) in a medical center in Ouagadougou. The PanbioTM COVID-19 Ag test was evaluated from January 26 to March 31, 2021 in symptomatic and asymptomatic patients in the medical Centre of Kossodo. A total of 268 individuals were tested by both SARS-CoV-2 RT-PCR, and antigen RDT. Of these 268 individuals, 52 were positive and 216 were negative for COVID-19 RT-PCR. The performance parameters of the test and its Kappa agreement with the RT-PCR were calculated according to the presence or absence of symptoms in the patients on one hand, and according to the time onset of symptoms on the other hand. The sensitivity of the PanbioTM COVID-19 Ag Rapid Test ranged from 29.63% (95% CI: 13.75 to 50.18) among COVID-19 asymptomatic patients, to 87.5% (95% CI: 52.91 to97.76) among symptomatic patients with symptom onset time of 1-5 days. Similarly, the PanbioTM COVID-19 Ag Rapid Test specificity was 97.3% (95% CI: 90.58 to 99.67) and 96.4% (95% CI: 91.81 to 98.82) in symptomatic and asymptomatic RT PCR negative patients. The PanbioTM COVID-19 Ag Rapid Test shows good performance in detecting COVID-19 cases in patients with a symptom onset time of less than seven (7) days. This performance is even better when the symptom onset is reduced to five (5) days. The results show that the antigen RDT is not suitable for COVID-19 detection among asymptomatic patients.
ABSTRACT
This study aimed to evaluate the application and diagnostic efficacy of two different colloidal gold kits for the detection of 2019-nCoV immunoglobulin M antibody (anti-IgM) and immunoglobulin G antibody (anti-IgG) in Beijing, a low endemic area, and to guide the rational clinical application. The sera of 29 patients with confirmed novel coronavirus pneumonia (COVID-19) and 19 411 patients from the non-infected screening population were selected to evaluate the sensitivity, specificity and false-positive rate of the 2019-nCoV antibody test kits from Zhuhai Lizhu and Tangshan Innotek using colloidal gold immunochromatography. The sensitivity of Inotec 2019-nCoV was slightly higher than that of Lizhu 2019-nCoV, with a sensitivity of 58.62% and 55.17%, respectively;the specimen collection time of the all-negative group was significantly less than that of the antibody-positive group (P < 0.05);the false-positive rate of the two reagents in the low-prevalence area was 0.16%, and the false-positive rate of 2019-nCoV IgG was higher in Inotec than in Lizhu. The false positive rate for 2019-nCoV IgM was significantly higher than that for IgG for the same brand (Inotec ?2=14.756 09, P=0.000 0;Lizhu ?2=27.492 62, P=0.000). Conclusion The 2019-nCoV antibody test is rapid, simple and easy to perform, with high specificity, and can be used as a rapid screening indicator for new crowns;the specificity, correctness and negative predictive value of the two kits are good, and the application of the other kit for retesting when a positive result occurs can reduce the false positive rate of informing the clinic;the application and analysis of positive reports of new crown antibodies should be combined with the endemic area and clinical comprehensive judgment.
ABSTRACT
We wished to understand the dynamic changes in production of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies in sera collected from coronavirus disease 19 (COVID-19) patients. Fifty-eight serum samples from 33 patients confirmed to have COVID-19 in Gansu Province, China, were tested for three types of SARS-CoV-2-specific antibodies: immunoglobulin (Ig) M, IgG, and total antibodies. The positive rate of IgM, IgG and total antibodies increased gradually with COVID-19 progression. Within the first 3 days, the positive rate of detection of SARS-CoV-2-specific antibody using the three kits was 13.6%-31.8%. whereas, within 4-7 days, it was 36.4%-45.5%, within 8-14 days it was 55.6%-77.8%, and after 15 days, it was 100%. In addition, the three kits were used to measure antibodies from serum samples collected from healthy people, and the specificity was 99%-100%. Statistical analyses indicated no significant difference among the results of the three kits (P > 0.05 for all). In summary, the three SARS-CoV-2 antibody-detection kits had good sensitivity and specificity for detection of antibodies against SARS-CoV-2, and could aid the clinical diagnosis of COVID-19. The dynamic characteristics of production of SARS-CoV-2- specific antibodies could provide important scientific bases for epidemiologic investigations.
ABSTRACT
Objective. To evaluate the operative capacity of nine serological rapid tests to detect the IgM/IgG antibodies response in serum from patients with SARS-CoV-2 in different clinical stages. Methods. A cross-sectional study of serological rapid tests was designed to compare the performance of the evaluated immunochromatographic tests for the diagnosis of SARS-CoV-2. A total of 293 samples was used, including negatives, asymptomatic, and symptomatic serum samples. Results. The sensitivity of the evaluated tests was low and moderate in the groups of asymptomatic serum samples and the group of serums coming from patients with less than 11 days since the onset of the symptoms. The specificity for the anti-SARS-CoV-2 antibodies tests ranged between 86.5%-99% for IgM and 86.5%-99.5% for IgG. The sensitivity and the likelihood ratio were different according to the study groups. The usefulness of these tests is restricted to symptomatic patients and their sensitivity is greater than 85% after 11 days from the appearance of symptoms. Conclusions. Serological tests are not an adequate strategy for the identification of asymptomatic and pre-symptomatic patients. Serological rapid tests for the detection of specific anti-SARS-CoV-2 antibodies can be used as a diagnostic aid, but diagnosis must be confirmed by RT-PCR. Rapid tests should be reserved for patients with symptoms lasting more than 11 days.
ABSTRACT
Infectious bronchitis virus (IBV) causes an acute, highly contagious viral respiratory disease in poultry with huge economic impact and extremely difficult to control due to its multiple serotypes. The disease could be prevented by rapid diagnosis either molecular or serological test. However, the later test is inexpensive such as heamagglutination inhibition test (HI), but IBV fail to give Heamagglutination (HA) reaction without pretreatment. Therefore, we designed this study for preparation of IBV antigen by treating with different enzymes for HA reaction. IBV local isolates were characterized by SDS-PAGE and RT-PCR. The indigenous isolate HA antigens were treated with different proteolytic enzymes trypsin, neuraminidase and phospholipase C. The prepared antigen were stored at -86oC and used for HA test. All antigen prepared by different enzyme were found to give significant HA titer up to 7 log2 . During stability test antigen prepared by phospholipase C were found most stable up to six month by giving constant 7 log2 HA titer, while neuraminidase induced antigen were stable up to five months (7 log2). Trypsin treated antigen were readily lost its activity from 7 log2 to 2 log2 after two months of incubation. During specificity test all antigens showed specific effect on IBV by eliciting agglutination of RBCs while other avian viruses avian influenza (AI), new castle disease virus (NDV) and infectious bursal disease virus (IBDV) were not affected by enzymatic inductions. Therefore, the antigen prepared by phospholipase C has been found to be more effective for HI test for rapid diagnosis of IBV during infection.
ABSTRACT
In December 2019, the coronavirus disease COVID-19 began in China. Since then, millions of infections and deaths from this cause have been reported worldwide, particularly among health workers who have suffered the harsh onslaught of the pandemic in the context of healthcare systems collapsed by demand. In this sense, the objective of this work was to determine the prevalence, sociodemographic, epidemiological, and clinical characteristics of COVID-19 present in health workers of the "Instituto Aut..nomo Hospital Universitario de Los Andes" in M..rida-Venezuela. An observational, retrospective, single-center, documentary study was carried out, where 297 clinical-epidemiological records corresponding to 285 health workers were analyzed, in a period between March 16 and November 30, 2020. The records were separated into two groups, front-line workers and support workers. The overall positivity of the RT-PCRs performed was 31.6%. The frequency of positive confirmatory results was highest among support workers at 33.9%. Nursing staff had the highest positivity (39.5%). A seroprevalence of 34.3% was found in immunological tests. The prevalence of SARS-CoV-2 infection among health care workers was higher among support workers compared to front-line workers. Therefore, general and work-specific prevention strategies should be strengthened to limit the spread of SARS-CoV-2 among staff to ensure that they perform safely and effectively.
ABSTRACT
Objective: To understand the change characteristics of respiratory pathogens in hospitalized children with respiratory tract infection in Shunyi district of Beijing from 2019 to 2020, and to provide basis for the prevention and treatment of respiratory tract diseases in children.
ABSTRACT
Aim: The test, based on the detection of SARS-CoV-2 antigen, is often seen as an alternative to the PCR method in connection with the need for screening of larger populations. In order to assess the suitability of such an approach, we evaluated the sensitivity of two antigenic assays on a group of individuals, including both patients with symptoms of covid-19 and asymptomatic and healthy individuals.
ABSTRACT
Nationwide shortages of tests that detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and diagnose coronavirus disease 2019 (COVID- 19) have led the US Food and Drug Administration (FDA) to significantly relax regulations regarding COVID-19 diagnostic testing. To date the FDA has given emergency use authorization (EUA) to 48 COVID-19 in vitro diagnostic tests and 21 high complexity molecular-based laboratory developed tests, as well as implemented policies that give broad authority to clinical laboratories and commercial manufacturers in the development, distribution, and use of COVID-19 diagnostic tests. Currently, there are 2 types of diagnostic tests available for the detection of SARS-CoV-2: (1) molecular and (2) serological tests. Molecular detection of nucleic acid (RNA or DNA) sequences relating to the suspected pathogen is indicative of an active infection with the suspected pathogen. Serological tests detect antibodies against the suspected pathogen, which are produced by an individual's immune system. A positive serological test result indicates recent exposure to the suspected pathogen but cannot be used to determine if the individual is actively infected with the pathogen or immune to reinfection. In this article, the SARS-CoV-2 diagnostic tests currently approved by the FDA under EUA are reviewed, and other diagnostic tests that researchers are developing to detect SARS-CoV-2 infection are discussed.