lateral flow assay

侧流测定
  • 文章类型: Journal Article
    HIV阴性患者的隐球菌病可能是机会性或地方病。尚未发表有关使用手指刺破全血(即时护理)隐球菌抗原侧流测定(CrAgLFA)诊断HIV阴性患者隐球菌病的研究。我们在圣保罗的两个中心进行了HIV阴性隐球菌病患者的病例系列研究,巴西。目的是确定手指刺破的全血CrAgLFA的敏感性,并描述该人群的主要特征。我们确定了30例HIV阴性隐球菌病患者[19例(63%),男性;中位年龄,47年]。10例(33%)患者免疫抑制,十个(33%)有其他合并症,和10(33%)明显有免疫能力,没有合并症。隐球菌病的部位分布如下:中枢神经系统,90%(n=27);肺,43%(n=13);和其他肺外部位,40%(n=12)。指刺全血CrAgLFA诊断隐球菌病的敏感性为97%(29/30)。在26名隐球菌性脑膜炎患者中,检测脑脊液的敏感性如下:CrAg乳胶凝集,77%(20/26);CrAgLFA,96%(25/26);和文化,81%(21/26)。培养物种在16例(62%)病例中鉴定出加蒂隐球菌,所有的人都有一个阳性的手指刺破全血CrAgLFA。该测试对HIV阴性患者的隐球菌病的诊断具有很高的敏感性,包括那些由C.Gattii引起的.
    Cryptococcosis in HIV-negative patients can be an opportunistic or endemic disease. There are no published studies on the use of the finger-prick whole blood (point-of-care) cryptococcal antigen lateral flow assay (CrAg LFA) for diagnosing cryptococcosis in HIV-negative patients. We conducted a case series study of HIV-negative patients with cryptococcosis in two centers in São Paulo, Brazil. The objectives were to identify the sensitivity of a finger-prick whole blood CrAg LFA and to describe the main characteristics of this population. We identified 30 HIV-negative patients with cryptococcosis [19 (63%), male; median age, 47 years]. Ten (33%) patients were immunosuppressed, ten (33%) had other comorbidities, and ten (33%) were apparently immunocompetent and without comorbidities. The distribution of the sites of cryptococcosis was as follows: the central nervous system, 90% (n = 27); pulmonary, 43% (n = 13); and other extrapulmonary sites, 40% (n = 12). The sensitivity of the finger-prick whole blood CrAg LFA for the diagnosis of cryptococcosis was 97% (29/30). Among 26 participants with cryptococcal meningitis, the sensitivity of testing cerebrospinal fluid was as follows: CrAg latex agglutination, 77% (20/26); CrAg LFA, 96% (25/26); and culture, 81% (21/26). Culture speciation identified Cryptococcus gattii in 16 (62%) cases, and all had a positive finger-prick whole blood CrAg LFA. This test presented high sensitivity to the diagnosis of cryptococcosis in HIV-negative patients, including those caused by C. gattii.
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    文章类型: English Abstract
    OBJECTIVE: Neutralizing antibodies against SARS-CoV-2 have shown to be an effective tool for the analysis of the immunity generated against COVID-19. Numerous seroprevalence studies carried out in different groups have made it possible to draw a global map of vaccination coverage through the use of rapid lateral flow immunochromatography serological tests for clinical and epidemiological purposes. The objective of our study was to determine the degree of immunity against SARS-CoV-2 associated with the presence of neutralizing antibodies in administrative staff, teachers and students at the University of Alicante by means of a rapid serological test and to learn about their experience with vaccination against COVID-19.
    METHODS: A cross-sectional epidemiological study was designed, based on the prevalence of antibodies against the S protein (spike) of SARS-CoV-2. A total of 888 people participated. The study was carried out with a single test (July 6 to July 22, 2021). Using logistic regression, adjusted Odds Ratios were calculated according to sex, age, type of vaccine, number of vaccine doses received, complete vaccination schedule, and having had COVID-19.
    RESULTS: The vaccines received mostly were Vaxzevria® and Comirnaty®, with 73.3% between both, although 67.2% presented a complete regimen. The results of the OJABIO rapid neutralizing antibody test gave a positive result in 61.4% of the sample. There was a high association between the variables COVID-19 infection, two doses of vaccine, Spikevax® or Comirnaty® vaccine, and eighteen/twenty-nine years old group with a positive result on the OJABIO test. A total of 712 subjects answered the parallel survey (80%) on adverse effects and preferences between the different vaccines against COVID-19.
    CONCLUSIONS: The vaccination status against COVID-19 in the university community after six months of the start of national immunization strategies reflects low coverage despite the excellent willingness to get vaccinated. Neutralizing antibodies (NAb) rapid tests can be useful to guide immunization strategies and decide when to administer new booster doses.
    OBJECTIVE: Los anticuerpos neutralizantes frente al SARS-CoV-2 han resultado una herramienta eficaz para el análisis de la inmunidad generada frente a la COVID-19. Numerosos estudios de seroprevalencia realizados en diferentes colectivos han permitido trazar un mapa global sobre la cobertura vacunal mediante el uso de pruebas serológicas rápidas de inmunocromatografía de flujo lateral con fines clínicos y epidemiológicos. El objetivo de nuestro estudio fue determinar el grado de inmunidad frente al SARS-CoV-2 asociado a la presencia de anticuerpos neutralizantes en personal administrativo, docentes y estudiantes de la Universidad de Alicante, mediante un test serológico rápido, así como conocer su experiencia sobre la vacunación frente a la COVID-19.
    METHODS: Se diseñó un estudio epidemiológico, transversal, basado en la prevalencia de anticuerpos frente a la proteína S (espícula o Spike) del SARS-CoV-2. Participaron un total de 888 personas. El estudio se llevó a cabo con un único test (6 de julio a 22 de julio de 2021). Mediante regresión logística se calcularon Odds Ratios ajustadas según sexo, edad, tipo de vacuna, número de dosis de vacuna recibidas, pauta completa de vacunación y haber padecido la COVID-19.
    RESULTS: Las vacunas recibidas mayoritariamente fueron Vaxzevria® y Comirnaty®, con un 73,3% entre ambas; el 67,2% presentó pauta completa. Los resultados del test rápido de anticuerpos neutralizantes OJABIO dieron un resultado positivo en el 61,4% de la muestra. La posibilidad de un resultado positivo en el test OJABIO estuvo fuertemente asociada a haber padecido la COVID-19, haber recibido dos dosis, estar vacunado con Spikevax® o Comirnaty® o pertenecer al grupo de dieciocho a veintinueve años. Un total de 712 sujetos respondieron a un cuestionario (80%) paralelo sobre los efectos adversos y las preferencias entre las distintas vacunas contra la COVID-19.
    CONCLUSIONS: El estado de vacunación frente a la COVID-19 en la comunidad universitaria a los seis meses de la puesta en marcha de las estrategias nacionales de inmunización refleja una baja cobertura asociada, a pesar de la excelente predisposición a vacunarse. Los test rápidos de anticuerpos neutralizantes (AcN) pueden ser de utilidad para orientar las estrategias de inmunización y para decidir el momento de administrar nuevas dosis de refuerzo.
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  • 文章类型: Multicenter Study
    目的:这项多中心研究的目的是比较侧流测定法(LFA)和酶联免疫吸附测定法(ELISA)的诊断性能,以检测血清和支气管肺泡灌洗液(BALF)样品中的Dynamiker曲霉半乳甘露聚糖水平。方法I.
    我们根据2021年12月\\\\\\\\\\\\\\\\分别通过LFA和ELISA分析免疫测定。
    结果:使用LFA检查半乳甘露聚糖,血清和BALF样本的敏感性分别为82.57%和89.47%,特异性为90.76%和92.00%,PPV分别为89.11%和96.23%,净现值分别为85.04%和79.31%,分别。在血清和BALF样品中使用两种方法观察到半乳甘露聚糖,显示PPA分别为95.11%和93.33%,NPAs分别为89.19%和96.30%,TPA分别为92.47%和94.25%,分别。ROC曲线表明,当指标值(I值)=0.5时,LFA具有最佳诊断价值,灵敏度为84.94%。特异性为90.97%。
    结论:与ELISA方法相比,LFA在血清和BALF样本中显示出优异的IA诊断性能,可用作IA患者早期诊断的检测方法。半乳甘露聚糖水平的动态变化可用于评估治疗反应。
    OBJECTIVE: The objective of this multicenter study was to compare the diagnostic performance of lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) to detect the Dynamiker Aspergillus Galactomannan levels in serum and bronchoalveolar lavage fluid (BALF) samples for I.
    METHODS: We registered 310 clinically suspected Aspergillus infection patients from December 2021 to February 2023 and classified them into subgroups as the \"IA group\" and \"non-IA group\" based on the latest EORTC/MSG guidelines. The immunoassays were analyzed by LFA and ELISA respectively.
    RESULTS: Galactomannan was examined using LFA, and serum and BALF samples demonstrated sensitivities of 82.57% and 89.47%, specificities of 90.76% and 92.00%, PPVs of 89.11% and 96.23%, and NPVs of 85.04% and 79.31%, respectively. Galactomannan was observed using two assays in serum and BALF samples and showed PPAs of 95.11% and 93.33%, NPAs of 89.19% and 96.30%, and TPAs of 92.47% and 94.25%, respectively. The ROC curve demonstrated that LFA had optimum diagnostic value when the index value (I value) = 0.5, the sensitivity was 84.94%, and the specificity was 90.97%.
    CONCLUSIONS: Compared to the ELISA method, the LFA has shown excellent performance for the diagnosis of IA in serum and BALF sample and can be used as an assay for the early diagnosis of patients with IA. The dynamic change in galactomannan levels may be useful for assessing treatment response.
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  • 文章类型: Journal Article
    背景:乳腺植入物相关的间变性大细胞淋巴瘤(BIA-ALCL)通常表现为植入物周围积液(血清肿)。CD30(TNFRSF8)是肿瘤细胞的一致标记物,但也可以由良性血清瘤中的活化淋巴细胞表达。BIA-ALCL的诊断目前包括细胞学和通过免疫组织化学或流式细胞术检测CD30,但这些研究需要专门的设备和病理学家的解释。我们假设CD30侧流测定(LFA)可以为可溶性CD30提供成本较低的快速测试,最终可由非专业人员用于BIA-ALCL的即时诊断。
    方法:我们对15例经病理证实的BIA-ALCL患者和10例良性血清瘤患者进行了CD30的LFA和酶联免疫吸附测定(ELISA)。为了确定LFA检测CD30的动态范围,我们以125pg/mL至10,000pg/mL的7种不同浓度将重组CD30蛋白添加到通用缓冲液中。然后,我们对10例经病理证实的BIA-ALCL患者和10例良性血清瘤的冷冻保存的血清瘤进行了CD30的LFA。
    结果:添加到通用缓冲液中的重组CD30蛋白在高于1000pg/mL的浓度下产生不同的测试线,在250-500pg/mL下产生微弱的测试线。LFA对所有未稀释的BIA-ALCL血清瘤和1:10稀释的10个恶性血清瘤中的8个产生阳性测试线,10例良性血清瘤中有3例未稀释为阳性,但在1:10稀释时全部为阴性。未稀释的CD30LFA的灵敏度为100.00%,特异性70.00%,阳性预测值为76.92%,BIA-ALCL的阴性预测值为100.00%。当标本以1:10稀释时,灵敏度降低至80.00%,但特异性和阳性预测值增加至100.00%,而阴性预测值降低至88.33%。当通过ELISA测量时,在六个良性血清中,CD30均低于1200pg/mL,而七个BIA-ALCL血清型含有>2300pg/mL的CD30水平,在所有情况下,除了一种情况下,从1:10或1:50的稀释度计算。
    结论:BIA-ALCL血清瘤可以通过CD30ELISA和LFA与良性血清瘤区分开来,但LFA需要更少的时间(<20分钟),并且可以由非专业人员在没有特殊设备的情况下进行,提示未来BIA-ALCL的即时检测可能是可行的。
    BACKGROUND: Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL) commonly presents as a peri-implant effusion (seroma). CD30 (TNFRSF8) is a consistent marker of tumor cells but also can be expressed by activated lymphocytes in benign seromas. Diagnosis of BIA-ALCL currently includes cytology and detection of CD30 by immunohistochemistry or flow cytometry, but these studies require specialized equipment and pathologists\' interpretation. We hypothesized that a CD30 lateral flow assay (LFA) could provide a less costly rapid test for soluble CD30 that eventually could be used by non-specialized personnel for point-of-care diagnosis of BIA-ALCL.
    METHODS: We performed LFA for CD30 and enzyme-linked immunosorbent assay (ELISA) for 15 patients with pathologically confirmed BIA-ALCL and 10 patients with benign seromas. To determine the dynamic range of CD30 detection by LFA, we added recombinant CD30 protein to universal buffer at seven different concentrations ranging from 125 pg/mL to 10,000 pg/mL. We then performed LFA for CD30 on cryopreserved seromas of 10 patients with pathologically confirmed BIA-ALCL and 10 patients with benign seromas.
    RESULTS: Recombinant CD30 protein added to universal buffer produced a distinct test line at concentrations higher than 1000 pg/mL and faint test lines at 250-500 pg/mL. LFA produced a positive test line for all BIA-ALCL seromas undiluted and for 8 of 10 malignant seromas at 1:10 dilution, whereas 3 of 10 benign seromas were positive undiluted but all were negative at 1:10 dilution. Undiluted CD30 LFA had a sensitivity of 100.00%, specificity of 70.00%, positive predictive value of 76.92%, and negative predictive value of 100.00% for BIA-ALCL. When specimens were diluted 1:10, sensitivity was reduced to 80.00% but specificity and positive predictive values increased to 100.00%, while negative predictive value was reduced to 88.33%. When measured by ELISA, CD30 was below 1200 pg/mL in each of six benign seromas, whereas seven BIA-ALCL seromas contained CD30 levels > 2300 pg/mL, in all but one case calculated from dilutions of 1:10 or 1:50.
    CONCLUSIONS: BIA-ALCL seromas can be distinguished from benign seromas by CD30 ELISA and LFA, but LFA requires less time (<20 min) and can be performed without special equipment by non-specialized personnel, suggesting future point-of-care testing for BIA-ALCL may be feasible.
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  • 文章类型: Journal Article
    弓形虫是一种原生动物寄生虫,可以感染包括人类在内的许多哺乳动物。猫是人类感染的主要来源之一。因此,用廉价的测试对猫进行常规筛查,快速,并且不需要精密的实验室设备很重要。在这项研究中,设计了一种侧流测定法(LFA)来快速诊断猫的弓形虫病。为此,我们选择了弓形虫的GRA1蛋白,因为它在诊断和疫苗研究中具有很高的抗原性。我们使用计算机工具进一步分析了GRA1蛋白的免疫学特性。然后,我们表达并纯化了重组GRA1(rGRA1)蛋白,并在LFA的开发过程中使用它来检测猫血清样品(n=40)中的弓形虫病。根据结果,rGRA1蛋白具有负GRAVY值,高脂肪指数,阿尔法螺旋,无规卷曲和12个B细胞表位。计算机上的数据支持rGRA1蛋白的高抗原特性,并表明它可以是LFA的良好抗原候选物。在30份猫阳性血清样本中,LFA发现27个为阳性,而LFA血清阴性血清(n=10)为阴性。初步数据显示LFA具有高灵敏度(90%)和特异性(100%)。当我们使用高响应猫血清(即用ELISA具有>0.5的光密度的血清)时,灵敏度值达到100%。这些结果表明,rGRA1蛋白是开发LFA以快速诊断猫弓形虫病的良好候选者。
    Toxoplasma gondii is a protozoan parasite that may infect many mammals including humans. Cats are one of the main sources of infection for humans. Therefore, routine screening of cats with tests that are inexpensive, rapid, and do not require sophisticated laboratory equipment is important. In this study, a lateral flow assay (LFA) was designed to rapidly diagnose toxoplasmosis in cats. For this purpose, we selected GRA1 protein of T. gondii due to its high antigenicity in diagnostic and vaccine studies. We further analyzed the immunological properties of GRA1 protein using in silico tools. Then, we expressed and purified recombinant GRA1 (rGRA1) protein and used it during the development of LFA to detect toxoplasmosis in serum samples (n = 40) of cats. According to the results, rGRA1 protein has negative GRAVY value, high aliphatic index, alpha helix, random coil and 12 B cell epitopes. The in silico data supported the high antigenic properties of rGRA1 protein and showed that it can be a good antigen candidate for LFA. Among 30 cat positive serum samples, 27 were found positive by the LFA while seronegative sera (n = 10) were negative by the LFA. The preliminary data showed that the LFA has high sensitivity (90 %) and specificity (100 %). When we used high responsive cat sera (i.e. sera that have optical density > 0.5 with ELISA) the sensitivity value reached 100 %. These results showed that rGRA1 protein is a good candidate to develop a LFA for rapid diagnosis of toxoplasmosis in cats.
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  • 文章类型: Multicenter Study
    背景:需要一种快速可靠的诊断测试,以通过早期诊断血液恶性肿瘤患者的侵袭性曲霉病(IA)来降低死亡率。
    目的:评估血清和支气管肺泡灌洗(BAL)曲霉半乳甘露聚糖侧流测定(GM-LFA)在IA诊断中的疗效,并确定GM-LFA与GM酶免疫测定(GM-EIA)的相关性。
    方法:在这项前瞻性多中心研究中,我们使用了血液系统恶性肿瘤和疑似IA患者的血清和BAL液样本,并进行了GM-LFA和GM-EIA.根据EORTC/MSGERC标准,患者被分组为已证实(n=6),可能(n=22),可能的IA(n=55),或无IA(n=88)。计算血清GM-LFA在0.5光密度指数(ODI)下的表现和曲线下面积(AUC)。进行Spearman相关分析和kappa统计以确定测试之间的一致性。
    结果:GM-LFA在已证实/可能的IA中显示AUC为0.832(灵敏度[SEN],特异性[SPE],负预测值[NPV],诊断准确率为75%,100%,92.6%,和93.9%,分别,ODI为0.5),与无IA的情况相比。GM-LFA和GM-EIA评分之间存在中度正相关(p=0.01)。在0.5ODI下观察到的测试之间的一致性几乎是完美的(p<0.001)。排除接受霉菌活性抗真菌预防或治疗的患者后,SEN,SPE,NPV,经证实/可能的IA的诊断准确率为76.2%,100%,93.3%,94.5%,分别。
    结论:血清GM-LFA在血液系统恶性肿瘤患者中显示出较高的鉴别能力和良好的诊断效能。
    BACKGROUND: A rapid and reliable diagnostic test is needed to reduce mortality through early diagnosis of invasive aspergillosis (IA) in patients with hematological malignancies.
    OBJECTIVE: To evaluate the efficacy of serum and bronchoalveolar lavage (BAL) Aspergillus galactomannan lateral flow assay (GM-LFA) in IA diagnosis and determine the correlation of GM-LFA with GM enzyme immunoassay (GM-EIA) in patients with hematological malignancies.
    METHODS: In this prospective multicenter study, we used serum and BAL fluid samples from patients with hematological malignancies and suspected IA and performed GM-LFA and GM-EIA. According to the EORTC/MSGERC criteria, patients were grouped as proven (n = 6), probable (n = 22), possible IA (n = 55), or no IA (n = 88). The performance of serum GM-LFA at 0.5 optical density index (ODI) and area under the curve (AUC) were calculated. Spearman\'s correlation analysis and kappa statistics were performed to determine the agreement between the tests.
    RESULTS: GM-LFA showed an AUC of 0.832 in proven/probable IA (sensitivity [SEN], specificity [SPE], negative predictive value [NPV], and diagnostic accuracy were 75%, 100%, 92.6%, and 93.9%, respectively, at a 0.5 ODI) versus that in no IA. A moderate positive correlation was noted between the GM-LFA and GM-EIA scores (p = 0.01). The observed agreement between the tests at 0.5 ODI was almost perfect (p < 0.001). After excluding patients who received mold-active antifungal prophylaxis or treatment, the SEN, SPE, NPV, and diagnostic accuracy for proven/probable IA were 76.2%, 100%, 93.3%, and 94.5%, respectively.
    CONCLUSIONS: Serum GM-LFA demonstrated high discriminatory power and good diagnostic performance for IA in patients with hematological malignancies.
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  • 文章类型: Journal Article
    未经证实:结核病(TB)是一种在野生动物-牲畜-人类界面上至关重要的疾病。
    UNASSIGNED:研究印度各州自由放养和圈养野生动物结核病的发生和分枝杆菌(M)物种。
    UNASSIGNED:总共396个来自印度国家公园的207种不同野生动物物种的临床样本,动物园,等。,通过侧流测定(LFA)进行分析,Ziehl-Neelsen(ZN)染色,和PCR。临床样本包括血液(n=156),粪便拭子(n=103),血清(n=73),和鼻拭子或躯干洗液(n=64)。
    未经证实:202只动物没有结核病的临床症状,尽管LFA对21只野生动物的致病性分枝杆菌抗原呈血清阳性。临床症状如体重逐渐下降,4只懒惰的熊(Melursusursinus)和一只大象(Elephasmaximus)表现出呼吸窘迫,LFA也呈阳性,PCR,和ZN染色。ZN染色显示9只(8.74%)粪便和9只(14.06%)鼻拭子或树干洗液中的抗酸杆菌(AFB)阳性。在7只懒熊和2只大象中发现了结核分枝杆菌,而牛分枝杆菌是通过物种特异性PCR在斑鹿(轴)中发现的。
    UNASSIGNED:野生动物中结核病生物的传播需要严格的监测计划,以确定这些动物的携带者状态,从而制定有效的结核病控制策略。
    UNASSIGNED: Tuberculosis (TB) is a disease of paramount importance at the wildlife-livestock-human interface.
    UNASSIGNED: To study the occurrence and Mycobacterium (M) species involved in the TB of free-ranging and captive wild animals in various Indian states.
    UNASSIGNED: A total of 396 clinical samples from 207 different wild animal species from various Indian national parks, zoological gardens, etc., were analyzed by lateral flow assay (LFA), Ziehl-Neelsen (ZN) staining, and PCR. Clinical samples include blood (n=156), faecal swabs (n=103), serum (n=73), and nasal swabs or trunk wash fluids (n=64).
    UNASSIGNED: Clinical signs of TB were absent in 202 animals, although 21 wild animals were seropositive for pathogenic Mycobacterium antigens by LFA. Clinical signs like progressive weight loss, and respiratory distress were exhibited by 4 sloth bears (Melursus ursinus) and an elephant (Elephas maximus), which were also found positive for LFA, PCR, and ZN staining. ZN staining showed positivity for acid-fast bacilli (AFB) in 9 (8.74%) faecal and 9 (14.06%) nasal swabs or trunk wash fluids of sloth bears (7 samples) and elephants (2 samples). M. tuberculosis was detected in 7 sloth bears and 2 elephants, whereas M. bovis was found in a spotted deer (Axis axis) by species-specific PCR.
    UNASSIGNED: The circulation of TB organisms in wild animals warrants a strict surveillance programme to identify the carrier status of these animals so that effective TB control strategies can be formulated.
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  • 文章类型: Journal Article
    侧流测定(LFA)是基于纸张的,设计用于在低资源环境中检测复杂样品中特定分析物的需求点测试。尽管LFA已成功用于不同的应用,当需要高灵敏度时,它的使用仍然有限,尤其是在早期疾病的诊断中。检测限(LOD)显然与用于实现视觉读出的信号生成系统有关,在许多涉及纳米颗粒与生物分子偶联的情况下,which,当合并时,提供敏感性和特异性,分别。虽然胶体金是目前使用最多的标签,正在开发其他检测系统。碳纳米颗粒(CNP)通过在论文背景中产生增加的对比度,显示出突出的特征来提高该技术的灵敏度。基于灵敏度提高的必要性,这项工作的目的是进行比较研究,在分析性能方面,在核酸侧流测定中,在商业链霉亲和素金纳米颗粒(streptAv-AuNP)和抗生物素蛋白碳纳米颗粒(Av-CNP)之间。通过DNA模板的连续稀释计算该方法的视觉LOD,范围从0.0到7pgμL-1/1.5×104CFUmL-1)。LFA使用Av-CNPs和使用streptAv-AuNP实现了低至2.2×10-2pgμL-1的视觉检测。这些LOD可以在没有任何仪器帮助的情况下获得。结果表明,CNPs显示出增加的灵敏度,即使通过目视检查也能达到纳摩尔范围。此外,CNP是最便宜的标签,和悬浮液是非常稳定和容易修改。
    A lateral flow assay (LFA) is a paper-based, point-of-need test designed to detect a specific analyte in complex samples in low-resource settings. Although LFA has been successfully used in different applications, its use is still limited when high sensitivity is required, especially in the diagnosis of an early-stage condition. The limit of detection (LOD) is clearly related to the signal-generating system used to achieve the visual readout, in many cases involving nanoparticles coupled to a biomolecule, which, when combined, provides sensitivity and specificity, respectively. While colloidal gold is currently the most-used label, other detection systems are being developed. Carbon nanoparticles (CNPs) demonstrate outstanding features to improve the sensitivity of this technology by producing an increased contrast in the paper background. Based on the necessity of sensitivity improvement, the aim of this work is a comparative study, in terms of analytical performance, between commercial streptavidin gold nanoparticles (streptAv-AuNPs) and avidin carbon nanoparticles (Av-CNPs) in a nucleic acid lateral flow assay. The visual LOD of the method was calculated by serial dilution of the DNA template, ranging from 0.0 to 7 pg μL-1/1.5 × 104 CFU mL-1). The LFA achieved visual detection of as low as 2.2 × 10-2 pg μL-1 using Av-CNPs and 8.4 × 10-2 pg μL-1 using streptAv-AuNPs. These LODs could be obtained without the assistance of any instrumentation. The results demonstrate that CNPs showed an increased sensitivity, achieving the nanomolar range even by visual inspection. Furthermore, CNPs are the cheapest labels, and the suspensions are very stable and easy to modify.
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  • 文章类型: Journal Article
    BACKGROUND: Aspergillus species meet the most important group of invasive fungal diseases (IFD) in immunosuppressed patients. Galactomannan is a polysaccharide antigen located in the wall structure of Aspergillus. The most commonly used method for antigen detection is enzyme-linked immunoassay (ELISA). Aspergillus galactomannan lateral flow assay (LFA) constitutes one of the new methods in the diagnosis of invasive aspergillosis (IA). The goal of this study was to demonstrate efficacy of LFA in our patients and to compare it to synchronous ELISA results.
    METHODS: Galactomannan antigen was examined using both LFA and ELISA in serum samples taken from patients who were followed up in our haematology clinic. All patients are classified in subgroups as \'proven\', \'probable\' and \'possible\' patients according to the last EORTC / MSG guideline. Patients who met the \'proven\' IA criteria were included in the study as the gold standard.
    RESULTS: A total of 87 patients were included in the study. Majority of patients had acute myeloid leukaemia (AML) (56.3%). Eleven (12.6%) were in \'proven\' IA group. LFA test showed a superior diagnostic performance compared with ELISA (LFAAUC  = 0.934 vs ELISAAUC  = 0.545; p < .001). The LFA had a sensitivity of 90.9% and a specificity of 90.8% for \'0.5 ODI\' in predicting IA (PPV = 55.8%; NPV = 98.6%; p < .001).
    CONCLUSIONS: The most important finding of this study is that the specificity of LFA was found to be higher for cut-off value of 0.5. It is recommended to combine the methods in many studies to provide a better early diagnosis for IA.
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  • 文章类型: Journal Article
    脑膜炎是球孢子菌病最具破坏性的形式。一个方便的,快速诊断方法可以早期治疗,避免许多脑膜炎并发症。我们研究了有记载的球虫病患者的脑脊液(CSF)样本,和控制,具有补体固定(CF),免疫扩散(ID)(“经典”试验),侧流测定(LFA;一条和两条),和两种酶免疫测定(EIA)。两条式LFA和EIA不仅能够分别检测IgG和IgM抗体,但也可以汇总每种方法的结果。具有ID的CF或IgG和IgM测试的总体使用被认为是最佳测试用途。在样品的1:21和1:441稀释度下评价LFA和EIA。将所有测定与真实患者状态进行比较。有49个病人标本和40个对照,这是CSF球虫诊断的最大比较研究.这些测试的灵敏度范围为71-95%,特异性为90-100%。IgM测定敏感性较低。在1:441的测定具有类似的特异性,但敏感性较低,表明样品的连续稀释可能导致产生滴度的测定。病例阳性结果的一致性为87-100%。当套件可用时,流行地区的医院实验室可以进行测试。LFA检测不需要实验室,使用简单,并给出快速的结果,甚至可能在床边。
    Meningitis is the most devastating form of coccidioidomycosis. A convenient, rapid diagnostic method could result in early treatment and avoid many meningitis complications. We studied cerebrospinal fluid (CSF) samples in patients with documented coccidioidal meningitis, and controls, with complement fixation (CF), immunodiffusion (ID) (the \"classical\" assays), lateral flow assays (LFA; one-strip and two-strip), and two enzyme immunoassays (EIA). The two-strip LFA and EIAs not only enabled separate testing for IgG and IgM antibodies separately, but also could aggregate results for each method. CF with ID or the aggregate use of IgG and IgM tests were considered optimal test uses. LFAs and EIAs were evaluated at 1:21 and 1:441 dilutions of specimens. All assays were compared to true patient status. With 49 patient specimens and 40 controls, this is the largest comparative study of CSF coccidioidal diagnostics. Sensitivity of these tests ranged from 71-95% and specificity 90-100%. IgM assays were less sensitive. Assays at 1:441 were similarly specific but less sensitive, suggesting that serial dilutions of samples could result in assays yielding titers. Agreement of positive results on cases was 87-100%. When kits are available, hospital laboratories in endemic areas can perform testing. LFA assays do not require a laboratory, are simple to use, and give rapid results, potentially even at the bedside.
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