Flow cytometry based rapid duplexed immunoassay for fusarium mycotoxins.

At small food processing facilities, the most frequently used test to determine if grain-derived mycotoxin concentrations are compliant with legal limits is the enzyme-linked immunosorbent assay (ELISA). Each kit is designed to detect one of the six dangerous mycotoxins. With the increasing occurrence of coinfection of grain with multiple-mycotoxins in the field and/or during storage, ELISA is no longer a cost effective best assay option.

Agreement in diagnosing occupational asthma by occupational and respiratory physicians who report to surveillance schemes for work-related ill-health.

Objectives: To assess diagnostic agreement for occupational asthma, and to identify case and rater characteristics associated with this diagnosis.

Methods: Summaries of possible occupational asthma cases were sent to 104 occupational and respiratory physicians. Raters assigned likelihood scores (0-100%) of occupational asthma based on case histories (phase 1), and on histories plus investigative procedures (phase 2).

Evaluation of a dry format reagent alternative for CD4 T-cell enumeration for the FACSCount system: a report on a Moroccan-Canadian study.

Background: Efforts to improve alternative CD4 T-cell counting methods are critical to accelerate the implementation of HIV antiretroviral therapy in resources limited regions. Substituting liquid format reagents to eliminate cold-chain transportation and refrigerated storage with dry format reagents contributes to higher efficiency supply management solution especially for laboratories at remote locations. ReaMetrix has developed dry format reagent kits compatible with the FACSCount system, a dedicated flow cytometer for T-cell subset enumeration widely used in resource limited settings.

Facilities for investigating occupational asthma in UK non-specialist respiratory departments.

Background: The facilities which should be available to physicians offering specialist occupational asthma services have recently been agreed upon by a UK panel of experts.

Aims: This study aimed to investigate whether these facilities are available in UK non-specialist secondary care respiratory departments and to document tertiary care referral patterns.

Methods: A random sample of 100 UK respiratory units was selected, and the lead consultant invited to participate.

A combined HIV-1 protein bead array for serology assay and T-cell subset immunophenotyping with a hybrid flow cytometer: a step in the direction of a comprehensive multitasking instrument platform for infectious disease diagnosis and monitoring.

Background: A new generation of bench-top flow cytometers with digital signal processing to perform suspension array technology (SAT) based bead array assays as well as leukocyte immunophenotyping is now available. These hybrid instruments provide an opportunity for the development of a more cost effective multitasking platform to support infectious disease treatment in resource limited countries.

Methods: We report the development and testing of two modules compatible with the hybrid flow cytometers.

Multiplexed and microparticle-based analyses: quantitative tools for the large-scale analysis of biological systems.

While the term flow cytometry refers to the measurement of cells, the approach of making sensitive multiparameter optical measurements in a flowing sample stream is a very general analytical approach. The past few years have seen an explosion in the application of flow cytometry technology for molecular analysis and measurements using microparticles as solid supports. While microsphere-based molecular analyses using flow cytometry date back three decades, the need for highly parallel quantitative molecular measurements that has arisen from various genomic and proteomic advances has driven the development in particle encoding technology to enable highly multiplexed assays.

Guidelines for performing single-platform absolute CD4+ T-cell determinations with CD45 gating for persons infected with human immunodeficiency virus. Centers for Disease Control and Prevention.

These guidelines were developed by CDC for laboratorians who perform immunophenotyping for detection and enumeration of CD4+ T-cells and other lymphocyte subsets in persons infected with human immunodeficiency virus (HIV). The guidelines describe single-platform technology (SPT), a process in which absolute counts of lymphocyte subsets are measured from a single tube by a single instrument. SPT incorporates internal calibrator beads of known quantity in the analysis of specimens by three- or four-color flow cytometry.

Report from a workshop on multianalyte microsphere assays.

Multiplexed assays using fluorescent microspheres is an exciting technique that has been gaining popularity among researchers, particularly those in the public health field. Part of its popularity is due to its flexibility, as both immunoassays and oligonucleotide hybridization assays can be developed on this platform. This report summarizes a workshop held by the Centers for Disease Control and Prevention that discussed issues surrounding these assays and the Luminex 100 xMAP instrument.

Impact of the international program for Quality Assessment and Standardization for Immunological Measures Relevant to HIV/AIDS: QASI.

Measurements of CD4 T-cell levels are essential for the assessment of human immunodeficiency virus (HIV) disease course, clinical staging, epidemiological studies, and decisions regarding prophylactic therapies against opportunistic infection. Until now, only in the industrialized countries was T-cell subset monitoring considered a practical option to assess disease progression. The Quality Assessment and Standardization for Immunological Measures Relevant to HIV/AIDS (QASI) program was established in 1997 to meet performance assessment for immunophenotyping laboratories in countries where such service is not available.

Evaluation of stabilized blood cell products as candidate preparations for quality assessment programs for CD4 T-cell counting.

Background: Exceptionally robust cell preparations are needed for quality assessment programs (QAPs) such as the International Program for Quality Assessment and Standardization for Immunological Measures (QASI) relevant to HIV/AIDS. A suitable product must withstand environmental stress related to transportation for a minimum of 6 days. The two objectives of this study are (1) to evaluate the performance of various commercial preparations with multicenter participation and (2) to evaluate the robustness of stabilized blood cell products.

Evaluation of a universal template for single-platform absolute T-lymphocyte subset enumeration.

The single-platform absolute T-lymphocyte subset analysis was evaluated utilizing a universal protocol in a Canadian multicenter study with the collaboration of the members of the Canadian HIV Trials Network (CTN). Participants used flow cytometers and reagents of their choice for labeling and lysing whole blood. Over a 2-year period, CTN laboratories performed single-platform absolute T-lymphocyte subset enumerations on fresh and commercial stabilized blood products using commercially available microfluorospheres TruCount and Flow-Count.

T-cell subset counting and the fight against AIDS: reflections over a 20-year struggle.

The story of T-lymphocyte subset immunophenotyping technology is reviewed on the occasion of the 20th anniversary of CD4 T-cell enumeration. Over time, immunophenotyping has evolved into precise, reliable, but complicated and expensive technology requiring fresh blood samples. The gating technologies that were universally adapted for clinical flow cytometry for the past decade relied on rapidly deteriorating morphological scatter characteristics of leukocytes.

Multiplexed immunoassays by flow cytometry for diagnosis and surveillance of infectious diseases in resource-poor settings.

An accurate, rapid and cost-effective diagnosis is the cornerstone of efficient clinical and epidemiological management of infections. Here we discuss the relevance of an emerging technology, multiplexed immunoassays read by flow cytometry, for the diagnosis of infectious diseases. In these assays, multiple fluorescent microspheres, conjugated to different antigens or antibodies, constitute the solid phase for detecting antibodies or antigens in biological samples.