scholarly journals VALIDATION OF THE ENZYME-LINKED IMMUNOSORBENT ASSAY FOR EMIQUANTITATIVE DETERMINATION OF IgM ANTIBODIES AGAINST CHLAMYDIA TRACHOMATIS

Author(s):  
Alexander Besarab
1983 ◽  
Vol 49 (6) ◽  
pp. 615-616
Author(s):  
A. M. van Loon ◽  
F. W. A. Heessen ◽  
J. T. M. van der Logt ◽  
J. van der Veen

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1363.3-1364
Author(s):  
G. Gridneva ◽  
E. Aronova ◽  
S. Glukhova ◽  
M. Cherkasova ◽  
B. Belov ◽  
...  

Background:An accessible and sensitive and sensitive method for determining antibodies to a new coronavirus infection is often the key to timely provision of the necessary medical care to patients with rheumatic diseasesObjectives:Compare methods for determining antibodies to SARS-CoV-2 using a rapid test and enzyme-linked immunosorbent assay (ELISA)Methods:Methods for determining antibodies to SARS-CoV-2 using an express test (Chromatographic express test SARS-CoV-2 IgG / IgM (Xiamen Biotime Biotechnology, China)) and by ELISA (Reagent kit for enzyme immunoassay of class G immunoglobulins and class M to SARS-CoV-2 (Vector-Best, Russia)) were compared.80 patients were included with a diagnosis of rheumatoid arthritis 26 (33%), psoriatic arthritis - 9 (11%), osteoarthritis - 15 (19%), rheumatic heart disease 1 (1%), SLE 2 (3%), deramtomyositis 3 (4%), systemic sclerosis 5 (6%), systemic connective tissue diseases 4 (5%), including Sjogren’s syndrome, spondyloarthritis 15 (19%).17 (21%) denied a history of COVID-19 symptoms. 63 (79%) noted any signs of COVID-19 3.095 ± 1.45 months before the test (Median 3 [2; 4] months). 63 (79%) noted any signs of COVID-19 109 ± 43 days before the test (Median 111 [78; 135] months). The ELISA method was considered the standard.Results:When comparing the results of the express test and the determination of IgG antibodies to SARS-CoV-2 in serum, the following was obtained: the sensitivity of the express test is 99%. When comparing the results of the express test and the determination of IgM antibodies to SARS-CoV-2 in serum, it was obtained: among 66 samples with a negative result by the express test method, IgM was detected in 6 cases by ELISA/ So, 7.5% of 80 samples were false negative. In 3 of 14 samples with a positive result by the express test, IgM by ELISA was not detected. So, 3.75% of 80 samples were false-positive. (Table 1). When comparing the results of the IgM express test and ELISA, the following was obtained: the sensitivity of the express test was 33%, the specificity was 85%.Table 1.Antibodies, express-testAntibodies (ELISA), absentAntibodies (ELISA), presentRowTotalsIgGabsent011Row %0.00%100.00%present37679Row %3.80%96.20%Totals37780IgМabsent60666Row %90.91%9.09%present11314Row %78.57%21.43%Totals71980Conclusion:When comparing the results of the express test and the determination of IgG antibodies to SARS-CoV-2 in serum, the sensitivity of the express test is 99%. Determination of IgM antibodies to SARS-CoV-2 using a rapid test is less reliable than determination using ELISA.Disclosure of Interests:None declared.


Author(s):  
J Grøndahl-HANSEN ◽  
N Agerlin ◽  
L S Nielsen ◽  
K Danø

An enzyme-linked immunosorbent assay (ELISA) was developed for the measurement of human urokinase-type plasminogen activator (u-PA) in plasma and serum. Microtiter plates were coated with a monoclonal antibody and incubated with standard or sample. Bound u-PA was quantitated with polyclonal antibodies conjugated with biotin, followed by avidin-peroxidase. The assay was 10-fold as sensitive as other previously reported ELISAs, the detection limit being approximately 1 pg of u-PA in a volume of 100 μl with a linear dose-response up to 15 pg of u-PA. The assay detected active u-PA and its inactive proenzyme form equally well and the recovery of both forms was higher than 90% in plasma. A variety of structurally related proteins, including t-PA, were tested, but no reaction with proteins other than u-PA and its amino-terminal degradation product were observed. The intra-assay and inter-assay coefficients of variation for determination of u-PA in plasma were 7.6% and 8.4%, respectively. The assay was equally applicable to serum. The values obtained with plasma and serum were similar, and the results were not affected by small variations in the preparation of the samples. The ELISA was used to measure the concentration of u-PA in plasma from 34 healthy donors. The mean values for u-PA in plasma from healthy donors was 1.1 ng/ml ± 0.3 ng/ml (SD) (range 0.6 - 1.5 ng/ml). No significant differences were found between men and women and no correlation between u-PA concentration and age could be demonstrated.The mean u-PA concentration in plasma from healthy donors obtained in this study is substantially lower than that reported by others. This might be due to different methods of determination of the protein content of the standard preparations or to differences in the specificity of the assays.


1990 ◽  
Vol 10 (4) ◽  
pp. 439-448 ◽  
Author(s):  
Won O. Song ◽  
Allen Smith ◽  
Carl Wittwer ◽  
Bonita Wyse ◽  
Gaurth Hansen

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