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: 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

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: We evaluated three indigenously produced immunochromatography (ICA) kits for the rapid detection of hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) by comparing them with a microparticle enzyme immunoassay (MEIA). METHODS: HBsAg and anti-HBs were tested by the ICA kits manufactured by three domestic companies, SD HBsAg and Anti-HBs (Standard Diagnostics, Inc., Yongin, Korea); Asan Easy Test(R) HBsAg and Anti-HBs (Asan Pharm Co., Ltd., Whasung, Korea); and GENEDIA(R) HBsAg Rapid Device and Anti-HBs Rapid Device (Green Cross MS, Inc., Yongin, Korea). RESULTS: Results by ICA agreed completely with those of MEIA in all the 20 HBsAg-negative sera and in all the anti-HBs-negative sera except one sample. Among the 20 HBsAg-positive sera by MEIA, 17 were positive by ICA using Green Cross MS, 16 using Asan Pharm Co., and 13 using SD and reverse passive hemagglutination. Among the 20 anti-HBs-positive sera by MEIA, 19 were positive by ICA using Green Cross MS and Asan Pharm Co., 17 using SD, and 18 by passive hemagglutination. Elapsed time for the control and test line to be visualized in ICA might be longer and the color of the lines lighter when using SD than Green Cross MS or Asan Pharm Co. CONCLUSIONS: Three indigenously produced ICA kits are as sensitive as MEIA for the detection of anti-HBs, but are less sensitive than MEIA for HBsAg. The ICA kits for the rapid detection of HBsAg might be recommended for a limited use in the clinical laboratory.
Chungcheongnam-do ; Gyeonggi-do ; Hemagglutination ; Hepatitis B Surface Antigens* ; Hepatitis B* ; Hepatitis* ; Immunochromatography* ; Immunoenzyme Techniques

BACKGROUND: This study was conducted to evaluate the usefulness of the BACTEC MGIT (Mycobacterium Growth Indicator Tube) 960 system for mycobacteria culture and immunochromatographic assay to identify Mycobacterium tuberculosis (MTB) in positive MGIT culture. METHODS: Mycobacteria-culture-positive cases were retrospectively analyzed from December 2010 to July 2011. The detection rates and the recovery times of the mycobacteria between the Ogawa media and the MGIT were compared. An immunochromatographic assay (ICA) (SD BIO-LINE) was also performed in the positive MGIT culture for identification, and the results were compared with those of the Ogawa media in the Korea National Tuberculosis Association. RESULTS: Among the 261 patients (M:F, 168:93; mean age, 61.6+/-17.16 yrs), 450 specimens (sputa, 365; bronchial washing, 61; and pleural effusion, 24) were found positive with mycobacteria. Mycobacteria were grown both on the MGIT and Ogawa media in 310 cases (68.9%); only on the MGIT in 115 cases (22.6%); and only on the Ogawa media in 25 cases (5.5%) (p<0.05).The recovery time was 28.2+/-8.9 days in the Ogawa media and 11.1+/-5.8 days in the MGIT (p<0.05). Among the 127 cases from the positive MGIT culture, all 92 cases that were confirmed as MTB cases bythe Korea National Tuberculosis Association were identified as MTB by ICA, with 100% sensitivity. CONCLUSION: MGIT increases the detection rate and shortens the recovery time of mycobacteria in clinical respiratory specimens, and the TB Ag MPT64 kit using ICA is useful in identifying MTB in a positive MGIT culture.
Humans ; Immunochromatography ; Korea ; Mycobacterium ; Mycobacterium tuberculosis ; Pleural Effusion ; Retrospective Studies ; Tuberculosis

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: 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: 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

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

BACKGROUND: Among the many methods estimating the quantity of beta-hCG for pregnancy testing in urine, immunochromatography is one of most widely used semi-quantitative detection method for its convenience to use and also for its rapid result reporting system. PREG-Q(TM) is a newly introduced semi-quantitative immunochromatography method for detecting b-hCG. Clinical usefulness of PREG-Q(TM) was evaluated as a screening test for early pregnancy detection. METHODS: Accuracy, detection limit, cross-reactivity with various glycoprotein hormones, interference study, and comparison study using total 100 urine samples from pregnant (50 samples) and non-pregnant women (50 samples) was evaluated. RESULTS: All the 50 urine samples of pregnant women showed positive results, and another 50 urine samples of non-pregnant women showed negative results with PREG-Q(TM). The lower detection limit of PREG-Q(TM) was 25 mIU/mL and the result was not affected by addition of glycoprotein hormones tested. Interfering substance causing false negative or false positive results enrolled didn't affect the test results in this study. CONCLUSIONS: We conclude PREG-Q(TM) is an excellent test kit for pregnancy test, and is valuable especially for detecting early pregnancy.
Female ; Glycoproteins ; Humans ; Immunochromatography ; Limit of Detection ; Mass Screening* ; Pregnancy Tests ; Pregnancy* ; Pregnant Women