TABLE 4.

Checklist of elements of the extraction validation criteria

Element(s) of extraction validation criteria
Specific target, namely, the virus, bacterium, fungus, or toxin, whether spores or vegetative cells are being recovered (spores generally need a more vigorous extraction method)
Assessment of whether the material or analyte needs to maintain viability or activity or is an inactive agent or material acceptable
Analyte(s) that will be assayed, e.g., DNA, RNA, protein, lipid, stabilizers, media, fatty acid, and other trace evidence and possibly combinations of these
Quantity of analyte needed for the subsequent analysis method(s)
Purity of the analyte required by the analytical method
Matrix effect, specifically, the matrix or substrate or material from which the target will be extracted (e.g., food, blood, soil, or carpet, etc.) and any known effects of the matrix on the extraction method; whether the application of the method to this matrix is still within the method scope; i.e., if the matrix is new and the effects are unknown, then the method may need to be revalidated with the new matrix
Recovery and efficiency of yield
Stability of the analyte prior to analysis (optimal storage conditions of the extracted analyte should be described)
Critical reagents
Critical equipment, such as bead beaters for spores and a fume hood for extractions involving volatile chemicals
Controls needed to assess the performance of the extraction process
Personnel training, proficiency, and safety