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17: Field laboratory methods

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    • 17.1: Introduction to field laboratory methods
      Laboratory tests may provide the definitive basis for the measurement of outcome variables in field trials, either directly by demonstration of the presence of the pathogenic agent under study or indirectly by demonstration of a host reaction or of biochemical changes due to the pathogen. They may also provide evidence of the mechanism of action of the intervention, for example, directly by measuring the drug or metabolic by-products or indirectly by measuring an immune response to a vaccine. In
    • 17.2: Sample collection
      Accurate laboratory results depend on proper collection, processing, and handling of samples. The method of collection, timing, and handling of samples will be determined by the purpose of the trial and specified in the trial protocol.
    • 17.3:Labelling and storage
      Proper labelling of samples is essential. The labelling scheme should be as simple as possible, consistent with the study objectives, and must take due account of the size of containers and how the specimens will be handled, transferred, and stored. In most cases, computer-generated, self-adhesive, pre-printed labels, with the individual identification or code numbers duplicated on data sheets, can speed processing. Also, labels in a variety of materials suitable for differing storage conditions
    • 17.4: Documentation of laboratory procedures
      There should be clear and explicit documentation of all laboratory procedures as SOPs in the laboratory manual, which should be subject to periodic review. The degree to which the documentation is computer-based will depend on local capacity and, to some degree, on the demands of the sponsors.
    • 17.5: Quality control and quality assurance
      QC is an inherent component of any good study and a good laboratory. It is a process of routine checks designed to detect any deficiencies that could compromise the results of laboratory analysis and suggest how these might be corrected. An example would be checks that the laboratory always gets the same result for a split specimen. QC checks should be specified in the laboratory work plan and in SOPs. A useful resource that discusses general laboratory QC issues is Ratliff (2003).
    • 17.6: Accreditation and links between laboratories
      In some cases, a field laboratory may be set up specifically for the conduct of a particular study and may have no regular links with other laboratories. Increasingly, however, there will be links with other laboratories, either as collaborative partners in projects or to provide specialized expertise and analysis.
    • 17.7: Coding and linkage of results
      In order to remove the possibility of bias, staff working in the laboratory should not know which trial arm any sample is from, and it should not be possible for this to be deduced from the labelling system employed. Specimens must be labelled in such a way,
    • 17.8: Laboratory health and safety
      Page notifications Off 17.7: Coding and linkage of results 17.9: References picture_as_pdf LMS Donate Table of contents Detailed attention to health and safety are key aspects of any laboratory. This may be of special importance in some field laboratories, as they may be relatively accessible by the public or have other specific safety risks.
    • 17.9: References
      Cheesbrough, M. 1987. Medical laboratory manual for tropical countries. London: Tropical Health Technology. Ratliff, T. A. 2003. The laboratory quality assurance system: a manual of quality procedures and forms.Hoboken, NJ: Wiley-Interscience.[Cross Ref]