# name
Analysis of factors affecting the variability of a quantitative suspension bead array assay measuring IgG to multiple Plasmodium antigens

# metadata.dc.description.abstract[].value
Reducing variability of quantitative suspension array assays is
                key for multi-center and large sero-epidemiological studies. To
                maximize precision and robustness of an in-house IgG multiplex
                assay, we analyzed the effect of several conditions on
                variability to find the best combination. The following assay
                conditions were studied through a fractional factorial design:
                antigen-bead coupling (stock vs. several), sample predilution
                (stock vs. daily), temperature of incubation of sample with
                antigen-bead (22°C vs. 37°C), plate washing (manual vs.
                automatic) and operator expertise (expert vs. apprentice). IgG
                levels against seven P. falciparum antigens with heterogeneous
                immunogenicities were measured in test samples, in a positive
                control and in blanks. We assessed the variability and MFI
                quantification range associated to each combination of
                conditions, and their interactions, and evaluated the minimum
                number of samples and blank replicates to achieve good
                replicability. Results showed that antigen immunogenicity and
                sample seroreactivity defined the optimal dilution to assess the
                effect of assay conditions on variability. We found that a
                unique antigen-bead coupling, samples prediluted daily,
                incubation at 22°C, and automatic washing, had lower
                variability. However, variability increased when performing
                several couplings and incubating at 22°C vs. 37°C. In addition,
                no effect of temperature was seen with a unique coupling. The
                expertise of the operator had no effect on assay variability but
                reduced the MFI quantification range. Finally, differences
                between sample replicates were minimal, and two blanks were
                sufficient to capture assay variability, as suggested by the
                constant Intraclass Correlation Coefficient of three and two
                blanks. To conclude, a single coupling was the variable that
                most consistently reduced assay variability, being clearly
                advisable. In addition, we suggest having more sample dilutions
                instead of replicates to increase the likelihood of sample MFIs
                falling in the linear part of the antigen-specific curve, thus
                increasing precision.

# metadata.dc.relation.isformatof[].value
Reproducció del document publicat a: http://dx.doi.org/          10.1371/journal.pone.0199278

# metadata.dc.source[].value
Articles publicats en revistes (ISGlobal)

# metadata.dc.title[].value
Analysis of factors affecting the variability of a quantitative suspension bead array assay measuring IgG to multiple Plasmodium antigens