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: To detect active tuberculosis, clinicians usually rely on several methods those are so limited. As the prevalence rate of tuberculosis is high in Korea, culture is not so very effective in clinical use. The polymerase chain reaction (PCR) featuring rapidness and high sensitivity offers low specificity and it requires high test cost, complicated skills, expensive equipment. This study attempted to determine if the immunochromatographic assay, intended to measure antibodies using 38 kDa antigens, is valuable as a new method to diagnose active tuberculosis, by comparing it with existing acid-fast stain (AFB stain) and PCR. METHODS: The sera were collected from 31 BCG-vaccinated healthy persons and 55 patients subjected to AFB stain and PCR who visited Pohang Hospital of Dongguk University or Kyungpook National University Hospital, and then kept at -20degrees C until experiment. Fifty-five patients subjected to AFB stain and PCR were composed of 24 active tuberculosis patients and 31 non-TB patients. The evaluation of active tuberculosis was based on clinical criteria. RESULTS: The detection rate of antibody by the immunochromatographic method accounted for 83% in the active TB group, and each 6% in both the non-TB group and the healthy control group. The sensitivities of AFB stain, PCR and immunochromatographic method accounted for 67%, 88% and 83%, respectively, the specificities for 94%, 86% and 94%, respectively, the positive predictive values for 89%, 84% and 91%, respectively, and the negative predictive values for 78%, 89% and 88%, respectively. CONCLUSIONS: This suggests that the immunochromatographic method can be used for the rapid diagnostic method of active tuberculosis in an area with high prevalence value of tuberculosis like Korea. In addition, the immunochromatographic method showed the sensitivity approximate to that of PCR, the same specificity as AFB stain, and a high positive and negative predictive values. So it was expected not only to be greatly helpful for the diagnosis of active tuberculosis but also to be more useful in clinical practices because of short examination time, no special equipment and skills required, and inexpensive examination.
Antibodies ; Diagnosis* ; Gyeongsangbuk-do ; Humans ; Immunochromatography* ; Korea ; Polymerase Chain Reaction ; Prevalence ; Sensitivity and Specificity ; Tuberculosis*

The followings are the results for external quality assessment (EQA) in immunoserology for 2004: 1. Evaluation of EQA was done in 2 trials in May and November, about 99% of laboratories participating average 8.4 items. EQA for anti-HBc test was newly started in 2004. 2. Commercial control, MASR Immunology Control from Medical Analysis Systems (Camarillo, CA, USA) was used to assure the quality of quantitative results of C-reactive protein (CRP), rheumatoid factor (RF) and anti-streptolysin O (ASO) tests in 2004. All the specimens for Immunoserology in EQA were delivered refrigerated for the first time, being received within 48 hours after sending. 3. EQA for detection of HBsAg mutants was tried for the first time, using the recombinant HBsAg mutant (Gly/Arg 145) kindly provided by Abbott Laboratories, USA. 4. The laboratories using immunochromatography assay (ICA) were increased, however, many laboratories using ICA reported falsely negative for the positive specimens. The sensitivity of ICA test kits as well as various factors influencing the ICA results should be evaluated. 5. Standardization of methods including calibrators for quantitative results should be required for the harmonization of results.
Allergy and Immunology ; C-Reactive Protein ; Hepatitis B Surface Antigens ; Immunochromatography ; Korea* ; Nephelometry and Turbidimetry ; Rheumatoid Factor

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: 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: 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: 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

We evaluated Immunochromatographic assay kit to screen HBsAg in human serum. When the reference HBsAg was applyed to ICA, HA and EIA kits, the limit of detection for HBsAg were found out to be 4, 2 and 0.25 ng/ml respectively. But ICA kit required 5 minutes to read the result whereas HA and EIA kit more than one hour. The sensitivity was 97% (29 of 30 samples) and the specificity 100% (45 samples) compared with conventional EIA. The ICA kit needs no instrument or machine to perform the test contrary to the conventional methods. Therefore, this rapid and sensitive ICA kit can be used for HBsAg-screening, especially in the emergency room and in the scene of the accident.
Emergency Service, Hospital ; Hepatitis B Surface Antigens* ; Hepatitis B* ; Hepatitis* ; Humans ; Immunochromatography* ; Limit of Detection ; Sensitivity and Specificity