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【Objective】 To evaluate the performance of absorption and elution test and real time PCR in identifying ABO blood group. 【Methods】 The blood samples with weakened antibody expression serologically were screened and analyzed by absorption and elution test, real time PCR and gene sequencing. The gene sequencing results were used as the gold standard to assess the consistency of the other two methods, and the sensitivity and specificity were compared. 【Results】 Compared with the sequencing results (gold standard), absorption and elution test showed moderate consistency, while real time PCR showed good consistency. Both the sensitivity and specificity of absorption and elution test and real time PCR were statistically different. 【Conclusion】 There was a good agreement between real time PCR and gene sequencing in identifying suspicious ABO blood group with weakened antibody expression serologically. Real time PCR, with a low misjudgment rate, has strong ability to detect weak antigen and is more conducive to identify blood type compared with absorption and elution test.
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Objective To develop an up-converting phosphor technology based lateral flow assay ( UPT-LF) to detect ricin toxin ( RT) quickly, accurately and quantitatively.Methods Ricin-monoclonal antibodies were prepared and their affinity was evaluated before four types of monoclonal antibodies with the highest titer were applied to couple with the up-converting phosphor nano-particles ( UCP-NPs) as the bio-conjugate and disperse on the analysis membrane as the test line, respectively.Following systematic optimization to establish the RT-UPT-LF strip, the sensitivity, precision, quantita-tive ability and specificity of RT-UPT-LF were evaluated.Results The detection could be accomplished within 15 min and the detection limit of the RT-UPT-LF assay could reach 0.5 ng/ml within the quantitative detection range of 0.5-1000 ng/ml.Other non-specific toxins at a concentration of 1000 ng/ml did not cause any non-specific reactions.Conclusion The developed RT-UPT-LF strip provides a new means for on-site quantitative detection of ricin toxin.
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<p><b>OBJECTIVE</b>To develop an up-converting phosphor technology based lateral flow (UPT-LF) assay for rapid and quantitative detection of Yersinia pestis, Bacillus anthracis spore and Brucella spp.and make the comparison with BioThreat Alert (BTA) test strips (Tetracore Inc., USA).</p><p><b>METHODS</b>Using up-converting phosphor nano-particles (UCP-NPs) as the bio-marker, three double-antibody-sandwich model based UPT-LF strips including Plague-UPT-LF, Anthrax-UPT-LF, Brucella-UPT-LF were prepared and its sensitivity, accuracy, linearity and specificity were determined by detecting 10(10), 10(9), 10(8), 10(7), 10(6), 10(5) and 0 CFU/ml series of concentrations of Y.pestis, B.anthracis, Brucella standards and other 27 kinds of 10(9) CFU/ml series of contrations of bacteria strains.Furthermore, the speed, sensitivity and accuracy of bacteria standards and simulated sample detection were compared between UPT-LF and BTA system.</p><p><b>RESULTS</b>The detection limit of Plague-UPT-LF, Anthrax-UPT-LF and Brucella-LF was 10(5) CFU/ml. The CV of series of bacteria concentrations was ≤ 15%, and the r between lg (T/C-cut-off) and lg (concentration) was 0.996,0.998 and 0.999 (F values were 1 647.57, 743.51 and 1 822.17. All the P values were <0.001), respectively. The specificity of Plague-UPT-LF and Brucella-LF were excellent, while that of Anthrax-UPT-LF was a little bit regretful because of non-specific reaction with two isolates of B. subtilis and one B.cereus. On-site evaluation showed the detection time of UPT-LF for all Y.pestis, B.anthracis spore and Brucella spp.was 33, 36 and 37 min, while BTA was 115, 115 and 111 min, which revealed the higher detection speed and sensitivity of UPT-LF comparing with BTA. The negative rate of two methods for blank standard was both 5/5, the sensitivity of UPT-LF for Y.pestis,B.anthracis spore and Brucella spp. was all 10(5) CFU/ml, then BTA was 10(6), 10(6) and 10(5) CFU/ml, respectively. The detection rate of UPT-LF for all three bacteria analog positive samples was 16/16, while BTA for B.anthracis was 7/16 only.</p><p><b>CONCLUSION</b>The good performance including rapidness, simplicity and high sensitivity will bring the bright future of UPT-LF to be broadly used on-site as first response to bio-terrorism.</p>
Assuntos
Bacillus anthracis , Brucella , Cromatografia de Afinidade , Peste , Sensibilidade e Especificidade , Esporos Bacterianos , Yersinia pestisRESUMO
Objective To develop an up-converting phosphor technology based lateral flow (UPT-LF) assay for rapid detection of Salmonella paratyphi A, S.paratyphi B, Escherichia coli O157 ∶H7 and Vibrio parahaemolyticus. Methods With up-converting phosphor nano-particles ( UCP-NPs ) as the bio-marker, four double-antibody-sandwich mode based UPT-LF strips for detecting the above mentioned four pathogens were prepared respectively and their sensitivi-ty, accuracy, linearity and specificity were evaluated .Furthermore, the feasibility of detecting bacteria in food samples was evaluated by different food samples artificially contaminated with less than 10 CFU target pathogens .Results The sensitivi-ty of UPT-LF assays for four pathogens was 105 ~106 CFU/ml with excellent specificity .The four strips had a good linear response with the linear fitting coefficient of determination (r) for each target pathogen ranging from 0.985 to 0.996.The positive rate of detecting pathogens from samples was acceptable .Conclusion The four developed UPT-LF strips provide a new choice for rapid , specific and sensitive and quantitative detection of S.paratyphi A , S.paratyphi B, E.coli O157∶H7 and V.parahemolyticus.