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@#Familial hypercholesterolemia (FH) is an autosomal dominant inherited genetic disease characterized by increased concentrations of low-density lipoprotein (LDL-C) cholesterol in the blood. The risk of premature coronary heart disease in FH patients may increase without early treatment. Advancement in molecular biology techniques has enable early detection and diagnosis of FH. These techniques are cost-effective and have a shorter turnaround time. The current diagnostic tools available for FH diagnosis involving algorithm-based scoring criteria and various molecular diagnosis methods including next-generation sequencing (NGS), Sanger sequencing, Multiplex ligation-dependent probe amplification (MLPA) and DNA hybridisation assay are discussed in this review. However, molecular genetic testing is not widely available due to time-consuming procedures, high cost and requires trained personnel. Thus, this 36 review highlights the use of point of care (POC) testing as an approach to diagnose FH, particularly in countries lacking infrastructure and expertise in this field. Lateral flow testing (LFA) has gained attention as a POC diagnostic tool due to its simplicity, low cost and involved simple procedure and settings. The advantages of LFA made this technique a potential tool in addressing challenges in diagnosing FH, particularly for early diagnosis of family members.
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Resumen La criptococosis meníngea presenta alta mortalidad mundial, especialmente en población VIH/sida. La OMS recomienda detectar el antígeno capsular de Crypto coccus como estrategia para un diagnóstico temprano y poder minimizar complicaciones. Objetivo: realizar antigenemia temprana de Cryptococcus mediante in munocromatografía/ensayo de flujo lateral en pacientes asintomáticos VIH+. Material y método: estudio descriptivo observacional; entre julio-2016 y mayo-2019 se procesaron mediante ensayo de flujo lateral, muestras de suero de 169 pacientes asintomáticos VIH+, con CD4 ≤120 cel/μL en Barranquilla, Colombia. Ante resultado positivo, se indicó profilaxis con fluconazol; se hizo seguimiento a todos los casos. Resultados: la antigenemia fue positiva en cinco pacientes (2,96%); uno falleció, cuatro recibieron profilaxis y la prueba se negativizó en dos. Los pacientes con resultado negativo inicial no desarrollaron durante el estudio sinto matología compatible con esta micosis. Discusión: el ensayo de flujo lateral de Cryptococcus está recomendado para el diagnóstico temprano de la criptococosis en población VIH/sida. Conclusión: detectar tempranamente el antígeno circulante de Cryptococcus mediante ensayo de flujo lateral en pacientes asintomáticos VIH+, permitió instaurar profilaxis oportuna, hacer seguimiento y control para reducir la mortalidad asociada con la criptococosis meníngea.
Abstract Meningeal cryptococcosis presents high levels of global mortality, especially in the HIV/AIDS population. The WHO recommends detecting the capsular antigen as an important strategy for early diagnosis and be able to minimize complications. Objective: Perform early cryptococcal antigenemia by immunochromatographic/ lateral flow assay in asymptomatic HIV+ patients. Material and method: descriptive observational study; between July-2016 and May-2019, serum samples from 169 asymptomatic HIV+ patients with CD4 ≤120 cells/μL were processed by lateral flow assay in Barranquilla, Colombia. Given a positive result, prophylaxis with fluconazole was indicated; all cases were followed up. Results: antigenemia was positive in five (2.96%) patients; one died; four received prophylaxis, and the test turned negative in two. The patients with an initial negative result, did not developed symptoms compatible with this mycosis during the study period. Discussion: lateral flow assay for Cryptococcus is recommended for the early diagnosis of cryptococcosis in the HIV/AIDS population. Conclusion: early detection of circulating Cryptococcus antigen by lateral flow assay in HIV+ patients allowed the establishment of timely prophylaxis, follow-up, and control to reduce mortality associated with meningeal cryptococcosis.
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Humans , Male , Female , Adult , Middle Aged , Acquired Immunodeficiency Syndrome , Cryptococcosis , CD4 Antigens , HIV , Aftercare , Cryptococcus , MeningitisABSTRACT
Abstract INTRODUCTION Lateral flow assay is an advanced method useful in the early diagnosis of cryptococcal meningitis. We aimed to compare two commercial tests for cryptococcal capsular antigen in the sera of asymptomatic patients with human immunodeficiency virus in Barranquilla, Colombia. METHODS Thawed (n=162) previously collected serums (2016-2019) were processed using IMMY and Dynamiker cryptococcal antigen lateral flow assay. RESULTS Compared to IMMY's results, Dynamiker's sensitivity, specificity, positive predictive value, negative predictive value, and kappa index were 100%, 89.9%, 48.3%, 100.0%, and 0.61, respectively. CONCLUSIONS The Dynamiker test had excellent sensitivity, acceptable specificity, and a low detection threshold for cryptococcal antigen in the tested samples.
Subject(s)
HIV Infections , Meningitis, Cryptococcal/diagnosis , Cryptococcus , Diagnostic Tests, Routine , Antigens, FungalABSTRACT
Lateral flow assay is widely used in the point-of-care testing on-site and in-home testing with the advantage of being simple, rapid, sensitive and cost-effective. Proper labels are the key factors in lateral flow assay. Traditional labels include colloidal gold, selenium nanoparticle, and carbon nanoparticle, among which the colloidal gold is most commonly used. Lateral flow assay has been improved as a result of the discovery of new labels, such as quantum dots and nanozyme recently. Meanwhile, transformation of qualitative detection to quantitative detection is gradually realized. This article aims at introducing the most often used and the latest lateral flow assay labels, providing a basis theoretical investigation on screening proper labels for lateral flow assay researchers.
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Immunomagnetic separation (IMS) was coupled with fluorescent microspheres lateral flow assay (FM-LFA) for rapid detection of S.choleraesuis in this study.The target bacteria were firstly enriched from sample by immunomagnetic beads (IMBs),then eluted by heat treatment and detected by fluorescent microspheres lateral flow test strip.The IMBs was labeled with 30 μg/mg antibody,and the capture efficiency was greater than 90％ against 102-106 CFU/mL of S.choleraesuis with great specificity.The immunofluorescent microspheres were prepared by coupling 300 μg of 11 D8-D4 monoclonal antibody with 1 mg of fluorescent microspheres at pH 6.Monoclonal antibody 5F11-B11 (2.0 mg/mL) and donkey anti-mouse IgG (1.0 mg/mL) were sprayed on nitrocellulose membrane as test line and control line,respectively.The FM-LFA based on IMS was used to detect S.choleraesuis in PBS and milk.The limits of detection in PBS buffer and milk were 1.5×105 CFU/mL and 7.6×105 CFU/mL respectively,which were 10 and 200 times lower than that of traditional fluorescent microspheres lateral flow assay,respectively.The results showed that the method,which could enrich S.choleraesuis in milk effectively,could avoid matrix interference and improve the detection sensitivity,thus had a good application prospect.
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<p><b>OBJECTIVE</b>To develop a rapid, highly sensitive, and quantitative method for the detection of NT-proBNP levels based on a near-infrared point-of-care diagnostic (POCT) device with wide scope.</p><p><b>METHODS</b>The lateral flow assay (LFA) strip of NT-proBNP was first prepared to achieve rapid detection. Then, the antibody pairs for NT-proBNP were screened and labeled with the near-infrared fluorescent dye Dylight-800. The capture antibody was fixed on a nitrocellulose membrane by a scribing device. Serial dilutions of serum samples were prepared using NT-proBNP-free serum series. The prepared test strips, combined with a near-infrared POCT device, were validated by known concentrations of clinical samples. The POCT device gave the output of the ratio of the intensity of the fluorescence signal of the detection line to that of the quality control line. The relationship between the ratio value and the concentration of the specimen was plotted as a work curve. The results of 62 clinical specimens obtained from our method were compared in parallel with those obtained from the Roche E411 kit.</p><p><b>RESULTS</b>Based on the log-log plot, the new method demonstrated that there was a good linear relationship between the ratio value and NT-proBNP concentrations ranging from 20 pg/mL to 10 ng/mL. The results of the 62 clinical specimens measured by our method showed a good linear correlation with those measured by the Roche E411 kit.</p><p><b>CONCLUSION</b>The new LFA detection method of NT-proBNP levels based on the near-infrared POCT device was rapid and highly sensitive with wide scope and was thus suitable for rapid and early clinical diagnosis of cardiac impairment.</p>
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Humans , Antibodies , Biomarkers , Heart Diseases , Diagnosis , Immunoassay , Methods , Infrared Rays , Natriuretic Peptide, Brain , Blood , Peptide Fragments , Blood , Point-of-Care Testing , Reagent Strips , Sensitivity and SpecificityABSTRACT
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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SUMMARYAIDS-related cryptococcal meningitis continues to cause a substantial burden of death in low and middle income countries. The diagnostic use for detection of cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid by latex agglutination test (CrAg-latex) or enzyme-linked immunoassay (EIA) has been available for over decades. Better diagnostics in asymptomatic and symptomatic phases of cryptococcosis are key components to reduce mortality. Recently, the cryptococcal antigen lateral flow assay (CrAg LFA) was included in the armamentarium for diagnosis. Unlike the other tests, the CrAg LFA is a dipstick immunochromatographic assay, in a format similar to the home pregnancy test, and requires little or no lab infrastructure. This test meets all of the World Health Organization ASSURED criteria (Affordable, Sensitive, Specific, User friendly, Rapid/robust, Equipment-free, and Delivered). CrAg LFA in serum, plasma, whole blood, or cerebrospinal fluid is useful for the diagnosis of disease caused by Cryptococcusspecies. The CrAg LFA has better analytical sensitivity for C. gattii than CrAg-latex or EIA. Prevention of cryptococcal disease is new application of CrAg LFA via screening of blood for subclinical infection in asymptomatic HIV-infected persons with CD4 counts < 100 cells/mL who are not receiving effective antiretroviral therapy. CrAg screening of leftover plasma specimens after CD4 testing can identify persons with asymptomatic infection who urgently require pre-emptive fluconazole, who will otherwise progress to symptomatic infection and/or die.
RESUMOA meningite criptocócica continua causando um substancial índice de óbitos em pacientes infectados por HIV em países de baixa e média renda. Ferramentas diagnósticas para detecção do antígeno capsular polissacarídico criptocócico (CrAg) em soro e líquor tais como o teste de aglutinação de látex (latex-CrAg) ou o imunoensaio (EIE) têm sido utilizadas por muitos anos. Técnicas diagnósticas mais aprimoradas seriam cruciais nas fases assintomática e sintomática da criptococose para reduzir a mortalidade. Recentemente, o ensaio de fluxo lateral para detecção do antígeno criptocócico (LFA CrAg) foi incluído no arsenal diagnóstico. Contrariamente aos outros testes, LFA CrAg é um ensaio imunocromatográfico em formato similar ao teste de gravidez, e requer pouca ou nenhuma infraestrutura laboratorial. Este teste preenche os critérios ASSURED (Affordable, Sensitive,Specific, User friendly,Rapid/ robust,Equipment-free,Delivered) da Organização Mundial da Saúde e pode ser utilizado em soro, plasma, sangue total ou líquor para o diagnóstico da criptococose. LFA CrAg tem melhor sensibilidade analítica para o C. gattii que o teste de látex-CrAg ou EIE. A prevenção da doença criptocócica constituiria uma nova aplicação do LFA CrAg, mediante a triagem de amostras de sangue para a identificação de infecção sub-clínica em pacientes infectados pelo HIV que não apresentam sintomas, possuem contagem de CD4 < 100 células/mL e não recebem terapia antirretroviral eficaz. A triagem de CrgA em amostras de plasma remanescente da contagem de CD4 pode identificar pacientes com infecção assintomática que precisam urgentemente de tratamento preemptivo com fluconazol, evitando assim a progressão para doença sintomática e/ou óbito.
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Humans , AIDS-Related Opportunistic Infections/diagnosis , Antigens, Fungal/immunology , Cryptococcus/immunology , Meningitis, Cryptococcal/diagnosis , AIDS-Related Opportunistic Infections/blood , AIDS-Related Opportunistic Infections/mortality , Antigens, Fungal/blood , Chromatography, Affinity , Meningitis, Cryptococcal/blood , Meningitis, Cryptococcal/mortality , Point-of-Care Systems , Sensitivity and SpecificityABSTRACT
Objective To develop an up-converting phosphor technology-based lateral-flow ( UPT-LF) assay for rapid detection of Listeria monocytogenes, named LM -UPT-LF.Methods Monoclonal antibodies against p 60, which was the specific virulence factor of L.monocytogenes,were prepared and covalently conjugated with up-converting phosphor nanopar-ticles (UCP-NPs) as bio-label.Then, LM-UPT-LF was established with double-antibody sandwich mode-based LF assay. Detection performance , including sensitivity and specificity , was evaluated .Results The samples with absolute contamina-ted amount of L.monocytogenes cells <10, 10-99, and 100-1000 cfu could be significantly detected as positive after in-cubation at 20 h, 18 h, and 16 h, respectively.Other 13 kinds of food-borne pathogens with concentration of 109 cfu/ml did not caused any non-specific reaction .Conclusion The established LM-UPT-LF assay could detect L.monocytogenes with high sensitivity , specificity and simplicity and provides an alternative method for food safety control .
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Objective To develop and evaluate an up-converting phosphor technology-based lateral flow assay ( UPT-LF) for detection of aflatoxin M1(AFM1) in milk powder and milk.Methods AFM1-UPT-LF was established with up-converting phosphor ( UCP) nano-particles as the bio-label of competitive mode based LF assay .Sensitivity, quantitative ability and precision were evaluated using simulated AFM 1-postive samples with serial standard concentrations .The qualita-tive and quantitative detection performance of AFM 1-UPT-LF was evaluated with reference to liquid chromatography-mass spectrography ( LC-MS) to detect samples of milk powder and milk simultaneously .Results AFM1-UPT-LF could conduct qualitative and quantitative detection without sample pretreatment within 20 min.The detection limit of AFM1-UPT-LF reached 0.1 μg/kg in milk powder and 0.3 μg/L in milk.There was good linearity ranging from 0.1 to 0.7 μg/kg and 0.3 to 0.7 μg/L for milk powder and milk, respectively.The sensitivity, specificity and receiver operating characteristic ( ROC) area under the curve ( AUC) of AFM1-UPT-LF for qualitative result could meet the need of national standards for AFM1 limit in dairy products.After statistical analysis, there was no significant difference (milk powder: t=0.66, P>0.05;milk:t=1.01, P>0.05) between AFM1-UPT-LF and LC-MS for quantitative detection .Conclusion The good qualitative and quantitative detection performance of AFM 1-UPT-LF for milk powder and milk makes possible on-site rapid detection of AFM1 in dairy products quantitatively .