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Dual signal-enhanced immunochromatographic test strip based on Au@PtNPs: From sensitive detection of thiamethoxam to multiplex pesticide screening in vegetables.

Immunochromatographic test strip (ICTS) is a rapid analytical technique widely used in environmental and food detection owing to its merits of simple operation and short analysis time. Herein, three-dimensional nanoflower-structured gold‑platinum nanoparticles (Au@PtNPs) were synthesized via a seed-growth method. Compared with conventional gold nanoparticles (AuNPs), Au@PtNPs exhibited stronger signal intensity, excellent catalytic performance, and efficient antibody binding efficiency. Colorimetric Au@PtNPs-ICTS and catalytic colorimetric Au@PtNPs-ICTS were developed for the sensitive detection of thiamethoxam (THI) in vegetables. The limits of detection (LODs) for colorimetric Au@PtNPs-ICTS and catalytic colorimetric Au@PtNPs-ICTS quantitative analysis were 0.18 ng/mL and 0.093 ng/mL, respectively, representing approximately 3-fold and 6-fold improvement compared to AuNPs-ICTS (0.56 ng/mL). Furthermore, highly sensitive detection of multiple pesticide residues (chlorpyrifos, acetamiprid, and imidacloprid) was achieved by replacing the corresponding target antigens and antibodies, which further verified the universality of this immunochromatographic strategy.

Thiamethoxam

Alpha-thalassaemia early eluting peak for alpha-thalassaemia --SEA carrier screening: a multicentre diagnostic comparison with immunochromatographic strip test and haemoglobin H inclusion test.

While high-performance liquid chromatography (HPLC) is well-established for &#x3b2;-thalassaemia and haemoglobinopathies, phenotypic screening for &#x3b1;0-thalassaemia has been limited. To address this limitation, we aimed to translate the discovery of the &#x3b1;-thalassemia early eluting peak (&#x3b1;EEP) in HPLC into clinical practice by comparing its diagnostic performance with other existing methods (haemoglobin H inclusion test [HbHi] and immunochromatographic strip test [ICT]) in a multicentre setting, and elucidating the nature of the &#x3b1;EEP by liquid chromatography-tandem mass spectrometry (LC-MS/MS). With a cohort of 820 genotyped patients, the &#x3b1;EEP showed superior diagnostic performance in detecting --SEA (sensitivity 99.6%, specificity 100%) compared with HbHi (sensitivity 95.8%, P&#x2009;=&#x2009;0.006; specificity 97.3%, P&#x2009;<&#x2009;0.001) and ICT (sensitivity 95.8%, P&#x2009;=&#x2009;0.006; specificity 75.4%, P&#x2009;<&#x2009;0.001). Both HbHi and ICT showed reduced sensitivity in &#x3b2;-thalassaemia carriers versus non-carriers. ICT showed reduced specificity when Hb F&#x2009;&#x2265;&#x2009;1% compared with <&#x2009;1%. The &#x3b1;EEP remained robust across all subgroups. LC-MS/MS revealed a strong association between the &#x3b1;EEP and embryonic &#x3b6;-globin chains (P&#x2009;<&#x2009;0.001). The &#x3b1;EEP offered cost reductions of 98.6% over HbHi and 97.3% over ICT. Collectively, the &#x3b1;EEP is a highly reliable and cost-effective marker for detecting --SEA carriers, enabling a novel "all-in-one" HPLC screening strategy for --SEA, &#x3b2;-thalassaemia and haemoglobinopathies. Trial registration number: not applicable.

Humans

Effectiveness of STK Spray&#xae; for semen stain localization on solid surfaces: A specificity and sensitivity study.

Semen identification is a crucial step in sexual assault cases. The aim of this study was to assess STK Spray&#xae;, a presumptive test for semen, under controlled conditions including, simulated crime scene stains detection. Easy to use, it can be sprayed directly onto different surfaces and visualized under UV light. Several tests were performed on five different substrates (ceramic tile, drywall, metal, wood, and faux leather). The spray was able to enhance semen fluorescence, especially in diluted samples, with characteristic "globular" spots. Although it showed good specificity, false positives could be obtained with 10% bleach. The fluorescence signals were quantified using ImageJ&#x2122; and showed a statistically significant substrate-dependent variability. Mixture analysis indicated that saliva did not interfere with detection of semen, while urine partially suppressed the signal and blood markedly affected its interpretation. Simulation tests with UV lamp comparisons confirmed the importance of choosing the right detection method and the utility of this presumptive test in combination with additional immunochromatographic tests. A preliminary signal retention test showed stable fluorescence for up to two years when stains were stored appropriately. Finally, complete DNA profiles (100% of alleles) were obtained from all samples (n&#xa0;=&#xa0;24) after exposure to the reagent and UV light. Because of its ability to enhance semen signal, especially on specific surfaces, and its rapidity of use and detection, STK Spray&#xae; may represent a useful aid in the preliminary screening phase.

Humans

Advances in diagnosis of diseases causing diarrhea in newborn calves.

Diarrhea in newborn calves is a serious global health problem. It poses challenges for animal industry, veterinarians and researchers due to the rapid onset of dehydration. Mixed infections make treatment complicated, and many young calves suffer high rates of illness and death from this condition. Numerous enteropathogens are associated with diarrhea in newborn calves, encompassing viruses, bacteria, parasites, and protozoa. Their occurrence differs by region, yet the most prevalent infections include E. coli, Salmonella species, Clostridium perfringens, Clostridium difficile, Rotavirus, Coronavirus, Cryptosporidium, Toxocara, Giardia and Eimeria. This review outlines the diagnostic techniques for diseases that lead to diarrhea in newborn calves. Diagnosis is based on clinical manifestations; however, the laboratory identification of etiological items is the only valid way for detecting the illness's aetiology and initiating treatment protocols. Classic methods such as bacterial culturing, fecal flotation, direct microscopy, and virus isolation help us understand pathogens better. Immunological assays like ELISA and immunochromatography are fast, accurate, affordable, and useful for on-farm detection. They help identify specific antigens or antibodies efficiently. Molecular methods including PCR (standard, multiplex, real time and digital), LAMP assays, DNA microarrays and whole-genome sequencing allow highly accurate and sensitive detection. They can identify pathogens effectively, even at very low levels. Nanotechnology-based assays introduce a novel level of sensitivity and specificity, often yielding quick results with minimal sample volumes. In conclusion, accurate and rapid diagnosis using advanced techniques is critical for managing and preventing diseases that lead to diarrhea in newborn calves.

Animals

Wildlife as a reservoir of OXA-48-like carbapenemase-producing Enterobacterales.

Carbapenemase-producing Enterobacterales (CPEs) have globally emerged and spread beyond human compartments. However, data in wild animals, especially from low- and middle-income countries, such as Algeria, are still very scarce. Here, we investigated CPEs recovered from feces samples collected between October 2021 and June 2023 from wild terrestrial and aquatic mammals, wild migratory/nesters/sedentary birds, and zoo animals, including their environment (water, food, and fecal samples of animal care workers) distributed over six Algerian provinces. Carbapenem-resistant Enterobacterales were characterized using MALDI-TOF-MS, Carba NP, immunochromatographic assay NG-Test CARBA 5, antimicrobial susceptibility testing, and whole-genome sequencing. Thirty CPEs were identified out of the 1,899 samples collected (1.6%). The carriage rate was higher in captive animals (3.2%) than in wild animals (1.2%). Twenty-six produced OXA-48, three OXA-244, and one OXA-181, along with CTX-M-15 ESBL. Clonal expansion of Enterobacter hormaechei hoffmannii ST145 and Klebsiella pneumoniae ST13 was evidenced. Plasmid analysis confirmed that 24/30 isolates harbored a transferable 62 kb IncL pOXA-48 plasmid. Five/six E. coli isolates belonged to high-risk clones with chromosome-mediated blaOXA-244 gene in three isolates, blaOXA-48 in two isolates, and blaOXA-181 gene encoded on an IncFII-ColKP3 hybrid plasmid in one isolate. This study showed widespread dissemination of OXA-48-like producing Enterobacterales in free and captive wild animals, largely driven by epidemic plasmids and clones. It underscores the role of wild animals as a reservoir of CPEs, particularly species living close to humans, such as gulls and pigeons, and occasionally food-producing animals, increasing the risk of bidirectional dissemination between animal, environmental, and human sectors.IMPORTANCEThe global rise of carbapenemase-producing Enterobacterales (CPEs) harboring blaOXA-48-like has been increasingly documented in clinical settings. However, their emergence and transmission in wild and captive animals are less documented. This study provides a high-resolution genomic characterization of CPEs isolated from the feces of wild animals, especially migratory birds, and from captive wild animals, to evaluate the potential risk of dissemination through these animals. Whole-genome sequencing data, genetic investigations, and antimicrobial susceptibility results highlighted the spread of multidrug-resistant CPEs in both animals and humans. The widespread detection of blaOXA-48 across multiple niches suggests sustained circulation beyond hospital settings in Algeria. Human-associated lineages, such as E. coli ST131, ST38, and ST540, were identified with a clear link with humans. This study demonstrates carriage of CPEs in multiple bird species living in areas commonly inhabited by humans and provides further evidence for an effective dissemination of resistance in wildlife, facilitated by feeding habits.

Animals

A modified hemagglutination inhibition test for estimating human follicle-stimulating hormone (hFSH) in unprocessed urine.

The development of a hemagglutination inhibition test for urinary human follicle stimulating hormone (hFSHu) is described. Antisera were raised in rabbits and absorbed immunochromatographically with crude preparations of human chorionic gonadotrophin (hCG). hFSHu was coupled to erythrocytes by means of bis-diazobenzidine. The reagents, alone or in combination were subjected to various specificity tests such as reactions of hFSHu-coated erythrocytes with antisera against different antigens, reactions of anti-hFSHu with erythrocytes coated with different antigens, and reaction of "non-FSH" preparations on different test combinations of anti-hFSHu sera and hFSHu-coated erythrocytes. A comparative assay of an hFSHu preparation with different reagent combinations appeared to give the most stringent criterion for specificity. A modified hemagglutination inhibition test system was developed according to the principle reported earlier for urinary human luteninizing hormone (hLHu). Its sensitivity was fixed at 2 mIU FSH/ml which is sufficient for the estimation of hFSH in unconcentrated urine.

Biological Assay

ZrO&#x2082;@C-based colorimetric/photothermal dual-mode immunosensor coupled with a novel monoclonal antibody for quantification of Aspergillus ochraceus biomass.

Aspergillus ochraceus contaminates agricultural products and produces nephrotoxic, carcinogenic ochratoxin A (OTA), posing severe food safety hazards. A dual-signal lateral flow immunochromatographic assay (dLFIA) based on ZrO&#x2082;@C nanoprobes was established for quantitative detection of A. ochraceus biomass. A novel monoclonal antibody (mAb 4B4) was prepared as the capture antibody to immobilize A. ochraceus mycelial lysate antigen on the test line, and a rabbit polyclonal antibody (pAb G2801) as the detection antibody to modify ZrO&#x2082;@C composites (synthesized via UiO-66 pyrolysis) into 200&#xa0;nm colorimetric/photothermal nanoprobes. This dLFIA achieved limits of detection of 0.164&#xa0;&#x3bc;g/mL (colorimetric) and 0.517&#xa0;&#x3bc;g/mL (photothermal). This efficient and reliable method allows quantitative analysis of A. ochraceus biomass, which is suitable for routine monitoring of fungal contamination in agro-food matrices.

Antibodies, Monoclonal

Evaluation of three Aspergillus antibody assays for screening of chronic pulmonary aspergillosis: prospective diagnostic accuracy study.

OBJECTIVES: Chronic pulmonary aspergillosis (CPA) is a frequent complication of pulmonary tuberculosis (PTB), particularly in high-burden settings where access to reliable serological diagnostics remains limited. We evaluated the diagnostic performance of two immunochromatographic technology (ICT) lateral flow assays (LFAs) and an ELISA for CPA screening among patients with active or previously treated PTB. METHODS: In this two-year prospective multicentre diagnostic evaluation, serum from adults with prior or active PTB was tested using the Era Biology Aspergillus IgG ICT LFA, LDBio Aspergillus IgG/IgM ICT LFA, and Bordier Aspergillus fumigatus IgG ELISA. CPA diagnosis was established using a consensus composite reference standard incorporating clinical, immunological, radiological, and microbiological criteria. The Bordier ELISA was used as part of the immunological component of the consensus CPA diagnosis, with a cutoff optical density of &#x2265;1.0. Diagnostic accuracy, agreement statistics, receiver operating characteristic analysis, and latent class analysis (LCA) were performed. RESULTS: Among 340 participants, 24 (7.06%) had CPA. Proportion of participants with positive antibody tests among all tested individuals were 6.76% for LDBio ICT LFA, 20.0% for Era Biology ICT LFA, and 11.47% for Bordier ELISA. Against consensus CPA diagnosis, Bordier ELISA showed 87.50% sensitivity and 94.30% specificity, LDBio ICT LFA 58.33% sensitivity and 97.15% specificity, and Era Biology LFA 66.67% sensitivity and 83.54% specificity. LCA estimated CPA prevalence at 7.72%. LCA-derived sensitivities and specificities were 86.58% and 99.92% for LDBio ICT LFA, 83.39% and 85.31% for Era Biology LFA, and 79.10% and 94.19% for Bordier ELISA. CONCLUSIONS: The Bordier ELISA showed high sensitivity and specificity, while the LDBio ICT LFA demonstrated very high specificity with strong LCA-derived performance. These findings support the use of ELISA for laboratory diagnosis and ICT as a point-of-care screening tool for CPA in resource-limited settings. Era Biology Aspergillus IgG LFA demonstrated moderate sensitivity and acceptable diagnostic performance, indicating its potential utility as a supplementary screening assay for CPA in settings where rapid, point-of-care testing is required.

Humans

Intravenous therapy of chronic obstructive pulmonary disease with sodium glycinate theophylline monitored by a new bed side theophylline assay.

Although the therapy of airway obstruction with theophylline is well established, unwanted side effects can occur: overdosage and reactions to ethylendiamine, an additive to increase the solubility of theophylline. Frequent measurements of the theophylline blood levels and the use of ethylendiamine free preparations can avoid such problems. Therefore, we studied the validity of a new immunochromatographic bed side assay (Acculevel) prior and after infusion of sodiumglycinate-theophylline (Theospirex) in 13 patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). Although theophylline levels increased above the therapeutic range (20 mg/L) in half of the patients after the infusion of 400 mg Theospirex in 1 hour, no toxic effects could be denoted. In addition, no influence on blood pressure and heart rate were found. We observed good correlations between this new immunochromatographic assay and theophylline levels measured with 2 well established reference methods (HPLC and turbidimetry, r = 0.87 and 0.91, respectively), although Acculevel revealed slightly higher values. Thus, the use of sodium-glycinate-theophylline and the new, fast bed side test system seems of practical importance in the therapy of COPD by potentially avoiding undesirable side effects.

Aged

Immunoelectron microscopic localization of T proteins in the cell wall of Streptococcus pyogenes.

T proteins of Streptococcus pyogenes (group A streptococci) were localized by means of immunochromatographical isolated anti-T-antibodies. For the electron microscopical detection both the direct and the indirect immunoferritin techniques were used. The arrangement of the ferritin particles showed, that the T proteins are evenly distributed on the whole cell surface. They are immediately bound to the outer layer of the cell wall or to only short filaments. On isolated cell walls the T protein was detected only on the outer surface.

Agglutination Tests

Molecular insights into carbapenemase-producing Enterobacterales from Senegal.

BACKGROUND: Carbapenemase-producing Enterobacterales (CPE) are an urgent global health threat, especially in resource-limited countries. Here we determined the prevalence and the molecular characteristics of CPE isolated from infections in Dakar, Senegal. METHOD: From January 2019 to December 2020, Enterobacterales with reduced susceptibility to ertapenem (diameter < 25&#x2005;mm) from infections were collected at the Pasteur Institute of Dakar. Carbapenemases were detected using biochemical and immunochromatographical assays. WGS was used to determine resistome, MLST, plasmids, virulence genes and genetic relatedness. RESULTS: Of the 1045 Enterobacterales collected during the study period, 86 had a diameter around ertapenem of <25&#x2005;mm (8%) and 19 were confirmed as CPE (2%). These included Escherichia coli (n&#x200a;=&#x200a;6) [ST410 (n&#x200a;=&#x200a;3), ST405 (n&#x200a;=&#x200a;2) and ST2083], Enterobacter spp. (n&#x200a;=&#x200a;6) [ST231 (n&#x200a;=&#x200a;3), ST245, ST760 and ST960] and Klebsiella spp. (n&#x200a;=&#x200a;5) (ST22, ST25, ST231, ST1535, ST4843), Citrobacter freundii ST22 (n&#x200a;=&#x200a;1) and Citrobacter koseri with unknown ST (n&#x200a;=&#x200a;1). blaOXA-48 (n&#x200a;=&#x200a;7; 35%), blaOXA-181 (n&#x200a;=&#x200a;7; 35%) and blaNDM-5 (n&#x200a;=&#x200a;6; 30%) genes were identified. C. freundii ST22 harboured blaNDM-5, blaOXA-48 and blaCTX-M-15 genes. Some E. coli isolates belonging to the high-risk clone ST410 were closely related (<20 SNPs) to isolates recovered in France from patients returning from Senegal, suggesting transnational spread. In addition, 5/6 carbapenemase-producing E. coli isolates possessed a four amino acid insertion in PBP3, conferring reduced susceptibility to aztreonam/avibactam and cefiderocol. CONCLUSIONS: This study highlights the spread of NDM-5 and OXA-181 in Senegal, and reports the first co-occurrence of NDM-5 and OXA-48 in sub-Saharan Africa. The spread of CPE, especially in high-risk clones, underscores the urgent need for continued surveillance and targeted interventions.

Senegal