OBJECTIVETo develop an up-converting phosphor technology-based lateral-flow (UPT-LF) assay for rapid quantitative detection of Burkholderia pseudomallei on site.

METHODSThe strip Bps-UPT-LF strip was prepared with up-converting phosphor (UCP) particles as the bio-label using double-antibody sandwich method. Detection performance, including sensitivity, quantitative accuracy, precision, and specificity, were first evaluated using bacterial suspensions of Burkholderia pseudomallei, the related species and the strains which had similar routes of transmission with serial standard concentrations diluted by phosphate buffer, then biological and chemical reagents and simulated samples with series concentrations were employed for sample tolerance evaluation, while the operation error during on site detection was also evaluated through adjusting liquid measure.

RESULTSThe whole detection was accomplished within 20 minutes, and the sensitivity was 10(4) CFU/ml with linear quantitative range from 10(4) CFU/ml to 10(7) CFU/ml, which covered four orders of magnitude. Bps-UPT-LF strip demonstrated high specificity with the absence of any false-positive result even at 10(7) and 10(8) CFU/ml of non-specific bacterial contamination. Not only Bps-UPT-LF strip could tolerate to high concentration of the extreme acid and basic matter (pH 1-12), saline matter (≤ 2 mol/L mixture of NaCl and KCl), viscous materials (≤ 50 g/L of PEG 20000 and ≤ 20% of glycerol) and bio-macromolecule (≥ 400 g/L of bovine serum albumin or ≥ 80 g/L of casein), but also it can directly detect animal, environmental and powder specimen, such as ≥ 400 g/L of milk powder, flour powder, fruit juice, fresh and decomposed viscera, and ≤ 200 g/L of putty powder, sucrose, gourmet powder, and soil. Operation errors of liquid measure had few effects on sensitivity and specificity, including -50%-200% of sample, -22%-44% of sample-treating buffer and -30%-30% of loading mixture.

CONCLUSIONThe good detection performance and tolerance performance bring the bright future for Bps-UPT-LF strip to detect Burkholderia pseudomallei on site rapidly and quantitatively for nature foci surveillance and anti-bioterrorism.

BACKGROUND: In the search for more powerful tools for diagnoses of endemic diseases in resource-limited settings, we have been analyzing technologies with potential applicability. Increasingly, the process focuses on readily accessible bodily fluids combined with increasingly powerful multiplex capabilities to unambiguously diagnose a condition without resorting to reliance on a sophisticated reference laboratory. Although these technological advances may well have important implications for the sensitive and specific detection of disease, to date their clinical utility has not been demonstrated, especially in resource-limited settings. Furthermore, many emerging technological developments are in fields of physics or engineering, which are not readily available to or intelligible to clinicians or clinical laboratory scientists. CONTENT: This review provides a look at technology trends that could have applicability to high-sensitivity multiplexed immunoassays in resource-limited settings. Various technologies are explained and assessed according to potential for reaching relevant limits of cost, sensitivity, and multiplex capability. Frequently, such work is reported in technical journals not normally read by clinical scientists, and the authors make enthusiastic claims for the potential of their technology while ignoring potential pitfalls. Thus it is important to draw attention to technical hurdles that authors may not be publicizing. SUMMARY: Immunochromatographic assays, optical methods including those involving waveguides, electrochemical methods, magnetorestrictive methods, and field-effect transistor methods based on nanotubes, nanowires, and nanoribbons reveal possibilities as next-generation technologies.
Endemic Diseases ; Health Resorts ; Immunoassay ; Immunochromatography ; Nanotubes ; Nanotubes, Carbon ; Nanowires

BACKGROUND: Broth cultures are increasingly used to detect acid-fast bacilli (AFB). Rapid, simple and accurate methods for differentiation of Mycobacterium tuberculosis complex (MTBC) and nontuberculosis mycobacteria from broth cultures are needed. Immunochromatographic assays (ICTs) for identification of MTBC have been developed. METHODS: The abilities of the BD MGIT TBc Identification Test (Becton Dickinson, USA) and the SD Bioline TB Ag MPT64 (Standard Diagnostics, Korea) to detect MTBC were evaluated in 44 AFB-positive broth cultures. The results of 2 ICTs were compared to those of real-time PCR. RESULTS: The BD MGIT TBc Identification Test and the SD Bioline TB Ag MPT64 showed concordant results with real-time PCR by 100% and 97.7%, respectively. The sensitivity of the BD MGIT TBc Identification and the SD Bioline TB Ag MPT64 was 100% for both, and the specificities of those were 100% and 95.2%, respectively. CONCLUSIONS: Both ICTs are rapid methods for identification of MTBC from broth cultures, and the results of ICTs are in accord with those of real-time PCR.
Immunochromatography ; Mycobacterium ; Mycobacterium tuberculosis ; Real-Time Polymerase Chain Reaction

OBJECTIVETo 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).

METHODSUsing 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.

RESULTSThe 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.

CONCLUSIONThe 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.

BACKGROUND: For the diagnosis of tuberculosis (TB), a variety of tests based on the patients' immune response has been introduced. We evaluated the clinical usefulness of combined anti-tuberculosis antibody (anti-TB Ab) test and Interferon-gamma release assay (IGRA), evaluating humoral and cellular immune response to Mycobacterium tuberculosis, respectively. METHODS: Among patients tested for IGRA, 78 patients diagnosed as TB and treated with anti-TB drug and 80 non-TB patients were included in this study. We used QuantiFERON-TB GOLD (QFT, Cellestis limited, Australia) for IGRA and an immunochromatographic assay, Easy Test TB (ASAN PHARM, Korea), for anti-TB Ab test. RESULTS: The sensitivity, specificity, and positive and negative predictive values of Easy Test TB were 23.1%, 98.8%, 94.7% and 56.8%, respectively. QFT had a significantly higher sensitivity than Easy Test TB (67.9% vs. 23.1%; P<0.05). The agreement between the two assays was poor (69.6%, k=0.190). Of the 18 cases with positive Easy Test TB, six (33%) showed negative QFT results. The combination of Easy Test TB and QFT had a significantly higher sensitivity than single QFT (75.6%, vs. 67.9%; P=0.031). CONCLUSIONS: The combination of Easy Test TB and QFT could be used to aid in a rapid diagnosis and early treatment of TB.
Humans ; Immunity, Cellular ; Immunochromatography ; Interferon-gamma ; Interferon-gamma Release Tests ; Mycobacterium tuberculosis ; Sensitivity and Specificity ; Tuberculosis

Mycobacterium tuberculosis complex (MTBC) is discriminated from non-tuberculous mycobacteria (NTM) via an immunochromatographic assay (ICA) which is based on the reactions of monoclonal antibodies against MPT64, one of the predominant proteins excreted by MTBC. Recently, the authors of the present study discovered SD TB-negative Mycobacterium tuberculosis strains. In addition, sequence analysis of the mpt64 genes in these strains was performed and showed a deletion of 63 bp from nucleotides 196 to 258. In cases of MPT64-negative mycobacterium, the authors recommend performing TB PCR for correct diagnosis.
Antibodies, Monoclonal ; Immunochromatography ; Mycobacterium ; Mycobacterium tuberculosis ; Nucleotides ; Polymerase Chain Reaction ; Proteins ; Sequence Analysis

BACKGROUND: Many diagnostic tests have developed to diagnose tuberculosis and other mycobacterial diseases but the diagnosis of tuberculosis relies largely on radiological findings and acid-fast staining of sputum and/or culture. Recently, new serologic diagnostic methods, which are safe and easy to use have been introduced into Korea. In this study, the usefulness of serologic diagnosis for tuberculosis and the disease pattern induced variation of the test were evaluated. METHODS: Serological assay was performed upon 108 patients with two test kits, the ICT tuberculosis and the BioSign(TM) TB, which are based upon a rapid immunochromatographic assay technique, capable of being interpreted within 15 minutes. The case groups consisted of 61 patients with active pulmonary tuberculosis(36 patients), extrapulmonary tuberculosis(3 patients), or both (22 patients). Control groups consisted of 47 patients with inactive old pulmonary tuberculosis (17 patients), nontuberculous pulmonary disease(16 patients) and nonpulmonary cardiac disease(14 patients). RESULTS: The diagnostic sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the ICT tuberculosis were 64.3%, 91.5%, 90.0% and 68.3% respectively. The diagnostic sensitivity, specificity, PPV and NPV of the BioSign(TM) TB were 76.5%, 95.3%, 94.1% and 78.8% respectively. Differences in sensitivity were not significant between patients with previous history of tuberculosis or patients without prior history of tuberculosis. The ICT tuberculosis test showed higher sensitivity in pulmonary tuberculosis patients (76.5%) than extrapulmonary tuberculosis patients (33.3%). There was no difference in sensitivity between patients with or without cavitary lesion by chest X-ray. CONCLUSION: Considering high specificity and PPV, serologic diagnosis using a rapid immunochromatographic assay device is another helpful diagnostic method in the diagnosis of tuberculosis, when combined with previous diagnostic methods such as chest X-ray, microbiologic study but it has limitation in terms of confirming the diagnosis for tuberculosis as the only diagnostic method because of relatively low sensitivity and NPV.
Diagnosis* ; Diagnostic Tests, Routine ; Humans ; Immunochromatography* ; Korea ; Sputum ; Thorax ; Tuberculosis* ; Tuberculosis, Pulmonary

BACKGROUND: Various assays including an enzyme immunoassay (EIA) are used to detect hepatitis B surface antigen (HBsAg) and antibody (anti-HBs). Recently, an increasing number of institutions have been utilizing an immunochromatography assay (ICA), which is rapid and easy to use and does not require special instrumentation; however, it is known to be less sensitive than EIA. In this study, we evaluated two different ICA kits for the detection of HBsAg and anti-HBs, and the results were compared with EIA. METHODS: A total of 400 serum samples, 100 each from HBsAg (+), HBsAg (-), anti-HBs (+) and anti-HBs (-) subjects, were assayed using two ICA kits (Daewoong, Genedia), and two chemiluminescence immunoassay (CIA) kits (ADVIA Centaur, ARCHITECT). The HBsAg and anti-HBs status had been determined by a microparticle enzyme immunoassay (AxSYM MEIA) at Seoul Paik Hospital. RESULTS: When compared with the results of AxSYM MEIA, the sensitivity, specificity, and concordance rate of both of the ICAs for HBsAg were 97%, 100% and 98.5%, respectively. The concordance rate, sensitivity, and specificities of Daewoong rapid Anti-HBs were 84.5%, 83%, and 86%, and the respective figures for Genedia rapid Anti-HBs were 85%, 96% and 74%. CONCLUSIONS: The diagnostic performances of two ICAs for HBsAg were more than 97%; however, both ICAs failed to detect HBsAg in low reactive samples. The concordance rate of two ICAs for anti- HBs was lower than that of three quantitative immunoassays. The results of ICAs should be interpreted with caution, because the samples containing a relatively low reactivity by the quantitative immunoassay can show negative results for anti-HBs.
Hepatitis B Surface Antigens* ; Immunoassay* ; Immunochromatography* ; Immunoenzyme Techniques ; Luminescence ; Sensitivity and Specificity ; Seoul

OBJECTIVES: The purpose of this study was to suggest a proper method for the detection of heaptitis B surface antibody(anti-HBs) in a screening program for hepatitis B vaccination. METHODS: Sensivitity, specificity and predictive values were compared between Immunochromatographic assay (ICA) and passive hemagglutination(PHA) in 978 subjects(565 males, 413 females, 19-78 years ranging in age, mean 46.5 years old). EIA was used as a standard method for the detection of HBsAb. RESULTS: Sensitivity in the detection of anti-HBs of PHA and ICA was 88.7% and 94.9%, specificity was 94.3% and 96.6%, negative predictive value was 96.5% and 98.0%, and positive predictive value was 82.3% and 91.3%, respectively. False negative rate(11.3%) of PHA was higher than that(5.1%) of ICA. The higher the titer of anti-HBs in EIA was, the lower the false negative rate was. There was no false negative result in the cases with 101mIU/ml or more in EIA. CONCLUSION: We suggest that ICA should be the choice of screening method in the detection of anti-HBs in Hepatitis B vaccination program.
Female ; Hepatitis B* ; Hepatitis* ; Humans ; Immunochromatography ; Korea* ; Male ; Mass Screening ; Sensitivity and Specificity ; Vaccination*

BACKGROUND: We analyzed the positive rates of Mediace Rapid Plasma Reagin (RPR) (Sekisui, Japan) and Mediace Treponema pallidum Latex Agglutination (TPLA) (Sekisui) assays. Positive results were compared to those of immunochromatography assay (ICA) and fluorescent treponemal antibody absorption (FTA-ABS) tests. METHODS: We used samples of patients visited at a university hospital from April 2010 to May 2011. The rates of positive results were calculated with 36,343 RPR results and 5,934 TPLA results. In addition, 237 positive samples with Mediace RPR or TPLA were re-tested with ICA and FTA-ABS. Mediace RPR and TPLA tests were performed with Toshiba 200-FR Neo (Toshiba, Japan). RESULTS: The rates of positive results were 0.47% (169/36,343) and 3.52% (209/5,934) with RPR and TPLA, respectively. Among the 237 sera that tested positive with RPR or TPLA, 76 were RPR(+)/TPLA(+), 28 were RPR(+)/TPLA(-), and 133 were RPR(-)/TPLA(+). When compared to the ICA results, 86.84% (66/76) of the RPR(+)/TPLA(+) sera were ICA(+), 3.57% (1/28) of the RPR(+)/TPLA(-) sera were ICA(+), and 54.89% (73/133) of the RPR(-)/TPLA(+) sera were ICA(+). Only 67.11% of the TPLA(+) sera demonstrated positive FTA-ABS results. However, 100% of the TPLA(-) sera yielded negative FTA-ABS results. ICA and FTA-ABS had a 96.59% positive agreement rate and an 80.68% negative agreement rate. CONCLUSIONS: These results demonstrate that Mediace TPLA has a low positive agreement rate with FTA-ABS. Although Mediace RPR and TPLA have advantages associated with automated methods, positive results should be confirmed with other treponemal tests, due to the high false positive rates.
Absorption ; Agglutination ; Humans ; Immunochromatography ; Latex ; Plasma ; Syphilis Serodiagnosis ; Treponema ; Treponema pallidum