
PDA Technical Glossary
PDA Technical Reports are highly valued membership benefits because they offer expert guidance and opinions on important scientific and regulatory topics and are used as essential references by industry and regulatory authorities around the world. These reports include terms which explain the material and enhance the reader’s understanding.
The database presented here includes the glossary terms from all current technical reports. The database is searchable by keyword, topic, or by technical report. Each definition provided includes a link to the source technical report within the PDA Technical Report Portal.
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Bias
A systematic difference in a method that manifests itself as a deviation of the method mean from an expected value. (TR57) Total systematic error, in contrast to random error. Measurement centered on the true result is said to be unbiased or have no systematic error. The distance between the center of a large (infinite) number of measurements and the correct value is the bias. (TR 57-2)
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Critical Reagent
A component of the test method that may have a substantial impact on the consistency and reliability of method performance. Features of critical reagents include: 1. A reagent that requires qualification of each new batch prior to routine use in an analytical procedure, or 2. A material whose method performance characteristics may change over time, during handling, or from lot to lot. 3. An analytical reagent that may be purchased only from a single vendor. Reagent Examples: antibodies or enzymes that require titration prior to use, tissue culture treated plates when only one vendor’s plates give acceptable results for a bioassay, growth factors for bioassay cells, conjugated proteins that require custom preparations, or reference or system suitability standards. (TR57) Function related: assay reagents that have been shown through development and/or robustness studies to have the potential to generate measurable differences that can significantly affect assay performance, such as sensitivity, specificity, and precision. (TR57-2)
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Design of Experiments (DOE)
A method for carrying out carefully planned experiments on a process. Usually, DoE involves a series of experiments that initially involves evaluating many variables and then focuses on a few critical ones. (TR54-4)
A structured, organized method for determining the relationship between factors affecting an assay and output of that assay. (TR57) (TR57-2) (TR74)
A structured, organized method for determining the relationship between factors affecting a process and the output of that process (8). (TR60)
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Factor
Independent variables that may influence assay outcome. (May be modified with confounded, crossed, fixed, interaction, level, modifying, nested, random). (TR57) (TR57-2)
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Matrix Effect
The direct or indirect alteration or interference in response due to the presence of additional sample components due to sample preparation (for analysis) or other interfering substances in the sample (product related excipients or residuals). (TR57) (TR57-2)
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Method Validation
A formal, archived demonstration of the analytical capacity of an assay that provides justification for use of the assay for an intended purpose. (TR56)
A formal, archived demonstration of the analytical capacity of an assay that provides justification for use of the assay for an intended purpose. Validations are conducted prospectively according to a written, approved plan that states acceptance criteria. (TR57) (TR57-2)
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Quality Attribute
A molecular or product characteristic that is selected for its ability to help indicate the quality of the product, such as identity, purity, potency stability and safety. (TR57) (TR57-2)
A molecular or product characteristic that is selected for its ability to indicate the quality of the product. Collectively, the quality attributes define identity, purity, potency, and stability of the product, and safety with respect to adventitious agents. Specifications measure a selected subset of the quality attributes. (TR60-2)