Jerry P. Smith

Interlaboratory comparison of three multiplexed bead-based immunoassays for measuring serum antibodies to pneumococcal polysaccharides.

ABSTRACT Serotype-specific IgG, as quantified by a standardized WHO enzyme-linked immunosorbent assay (ELISA), is a serologic end point used to evaluate pneumococcal polysaccharide-based vaccine immunogenicity. Antibodies to each vaccine polysaccharide in licensed multivalent vaccines are quantified separately; this is laborious and consumes serum. We compared three bead-based immunoassays: a commercial assay (xMAP Pneumo14; Luminex) and two in-house assays (of the Health Protection Agency [HPA] and Centers for Disease Control and Prevention [CDC]), using the WHO-recommended standard reference and reference sera (n = 11) from vaccinated adults. Multiple comparisons of the IgG concentrations for seven conjugate vaccine serotypes were performed by sample (percent error), serotype (equivalency testing), and laboratory (concordance correlation coefficient [CCC]). When comparing concentrations by sample, bead-based immunoassays generally yielded higher antibody concentrations than the ELISA and had higher variability for serotypes 6B, 18C, and 23F. None of the three assays met the current WHO recommendation of 75% of sera falling within 40% of the assigned antibody concentrations for all seven serotypes. When compared by serotype, the CDC and HPA tests were equivalent for five of seven serotypes, whereas the Luminex assay was equivalent for four of seven serotypes. When overall mean IgG concentrations were compared by laboratory, a higher level of agreement (CCC close to 1) was found among bead-based immunoassays than between the assays and WHO assignments. When compared to WHO assignments, the HPA assay outperformed the other assays (r = 0.920; CCC = 0.894; coefficient of accuracy = 0.972). Additional testing with sera from immunogenicity studies should demonstrate the applicability of this methodology for vaccine evaluation.

Analytical Performance Criteria

The past five years have seen a move towards standardizing the documentation of measurement uncertainty through nearly worldwide adoption of the International Organization for Standardization Guide...

Use of Direct Reading Surface Sampling Methods for Site Characterization and Remediation of Methamphetamine Contaminated Properties

Residual methamphetamine contamination in Clandestine laboratories represents a hazard to emergency response personnel, remediation workers and the general public. To address this threat, two rapid, sensitive surface sampling techniques to assess the location and level of methamphetamine contamination were developed. Both methods employ established industrial hygiene surface sampling materials (wipes and swabs) but differ in their sensitivity and detection technology. One method, based on colorimetric disclosure, detects and confirms a collected sample or visible residues. The second method uses a lateral flow immunochemical assay (LFIA) for semi-quantitative detection of trace contamination. The National Institute for Occupational Safety and Health (NIOSH) partnered with public health agencies to develop applications of the methods for assessment of methamphetamine contamination of suspected properties. These applications focused on safe strategies for site assessment, hazard characterization, and remediation effectiveness. To conduct the field studies, NIOSH researchers and their partners visited more than a dozen suspected laboratories including mobile labs, abandoned properties, occupied residences, and motel rooms. NIOSH found greater than 95% agreement between positive identification of the presence of methamphetamine by LFIA and laboratory-based, liquid chromatography mass spectroscopy (LC–MS) methods. Test results were used to develop site assessments and make personal protective equipment recommendations. Results were also used to conduct process-based decontamination of properties and to make health-based decisions on remediation, re-occupancy of residences, as well as determine the degree of contamination of personal property in an inactive clandestine laboratory. By partnering with stakeholders, NIOSH was able to achieve two primary goals: (1) to develop a level of awareness in health department sanitarians, law enforcement personnel and other first responders that methamphetamine surface contamination was a potentially significant route of exposure; (2) to validate our methods in the field and to develop protocols for proper use and interpretation of the results.

The use of immunochemical and biosensor methods for occupational and environmental monitoring. Part I: introduction to immunoassays.

The past five years have seen a move towards standardizing the documentation of measurement uncertainty through nearly worldwide adoption of the International Organization for Standardization Guide...

Analytical Performance Criteria: The Use of Immunochemical and Biosensor Methods for Occupational and Environmental Monitoring. Part II: Immunoassay Data Analysis and Immunobiosensors

T his is the second of a two-part series on the use of immunochemical and biosensor methods for occupational and environmental monitoring. In Part I (Introduction to Immunoassays), a general overview of the immunology and types of immunoassays was discussed. The major types of enzyme-linked immunosorbent assays (ELISAs), radioimmunoassays (RIA), and lateral flow techniques were described. In the present column, how data are reduced from immunoassays is addressed and some state-ofthe-art immunobiosensors are introduced.

Analytical Performance Criteria: The Use of Immunochemical and Biosensor Methods for Occupational and Environmental Monitoring. Part I: Introduction to Immunoassays

The past five years have seen a move towards standardizing the documentation of measurement uncertainty through nearly worldwide adoption of the International Organization for Standardization Guide...

Evaluation of the prevalence of anti-wheat-, anti—flour dust-, and anti-alpha amylase-specific IgE antibodies in blood donors*

Background: Asthma in bakery workers is one of the most frequently occurring forms of occupational asthma in the world. Experience from other countries has shown the prevalence of sensitization (IgE) to bakery-associated allergens (BAAs) (wheat [W], flour dust [FD], -amylase [AA]) in bakery workers to be 5% to 53%, whereas the prevalence in nonoccupationally exposed individuals was estimated to be 1.2% to 6.4%. Objective: To estimate the prevalence of BAA sensitization by measuring BAA specific IgE in the residual serum tubes of volunteer blood donors. Methods: Serum samples from 534 volunteer blood donors were measured for anti-W, anti-FD, and anti-AA specific IgE antibodies (in duplicate) using the AlaSTAT microplate assay. Samples with BAA IgE concentrations of 0.35 kU/L or greater were considered positive. Results: Nineteen of 530 serum samples (3.6%; 95% confidence interval [CI], 3.3%–3.9%) were positive for W (range, 0.38–3.61 kU/L), whereas 31 of 534 (5.8%; 95% CI, 5.3%–6.3%) were positive for FD (range, 0.35–2.34 kU/L) and 5 of 529 (1.0%; 95% CI, 0.9%–1.1%) were positive for AA (range, 0.38–1.59 kU/L). Thirteen serum samples were positive for both W and FD; 1 sample each was positive for W and AA and FD and AA. Conclusions: The prevalence of IgE sensitization in serum samples from a relatively large unselected population of volunteer blood donors is 1.0% for AA, 3.6% for W, and 5.8% for FD, which agrees well with data from other countries for sensitization prevalence rates for nonoccupationally exposed individuals. Ann Allergy Asthma Immunol. 2004;92:649–653.