Analytical and Bioanalytical Chemistry

, Volume 405, Issue 24, pp 7773–7782

Experimental design for in-house validation of a screening immunoassay kit. The case of a multiplex dipstick for Fusarium mycotoxins in cereals

  • Veronica M. T. Lattanzio
  • Christoph von Holst
  • Angelo Visconti
Research Paper
Part of the following topical collections:
  1. Rapid Detection in Food and Feed

Abstract

The benefits of using rapid qualitative methods to verify compliance of food and feed with legislation requirements include user-friendly format, the possibility of detection without expensive instrumentation, rapid response and affordable price. Prior to their use, however, the methods have to pass validation experiments, in order to assess their performance profile. An experimental protocol for in-house validation of a screening immunoassay has been designed and applied to evaluate performance characteristics of a multiplex dipstick kit for the determination of major Fusarium toxins, namely zearalenone, T-2 and HT-2 toxins, deoxynivalenol and fumonisins in wheat and maize. The test is intended for screening of cereals on the presence/absence of these mycotoxins at maximum permitted levels established by European legislation or target levels. The response of the measurement is determined with a reader device. Samples classified as negative are considered as compliant, whereas positive samples need to be re-analysed with confirmatory methods. The in-house validation design consisted of three steps, namely (1) estimating the precision of the method including "between day" effects and influences from different varieties of the matrices, (2) establishing robust cutoff values for the dipstick response at target mycotoxin levels assuming an acceptable rate of false negative results of 5 % and (3) assessment of the rate of false positive results of blank samples and samples containing the target analytes below the legal limits. The total precision expressed as relative standard deviation and determined individually for each analyte/concentration/matrix combination varied from 9 to 30 % and was considered as acceptable. In 17 out of 28 cases, the repeatability standard deviation was the most important factor. The predominance of the repeatability compared to the other factors (matrix, days) was an indicator for the ruggedness of the assay. The validation study demonstrated that the test was able to differentiate blank samples from samples contaminated at target mycotoxin levels with a false positive rate lower than 6 %. Considering realistic mycotoxin occurrence in European samples, significant economical benefits can be expected when using the test under real-world conditions.

Figure

Flow diagram of the experimental protocol for single laboratory validation of multiplex dipstick immunoassays

Keywords

Test kit validation Screening immunoassay Qualitative methods Fusarium mycotoxins Cereals 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Veronica M. T. Lattanzio
    • 1
  • Christoph von Holst
    • 2
  • Angelo Visconti
    • 1
  1. 1.Institute of Sciences of Food Production, National Research Council of ItalyBariItaly
  2. 2.European Commission, DG Joint Research CentreGeelBelgium

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