Final Disposition

Also included in the records should be a record of the final disposition of the sample and materials associated with it. Often, laboratories receive a sample for analysis without clear guidance as to how the customer or submitting agency wants the sample disposed of after analysis. In such cases, the laboratory should request written instructions from the agency, detailing the final disposition of the sample. If the sample evidence is returned, COC must once again be documented (note: COC should have already been established) and recorded in the sample documents and the analytical laboratory's records. Note that sample return involves certain risks. In scenarios where an agency has requested an analytical laboratory test for specific agents and all the analyses are reported as negative or below the sensitivity of the analytical procedure, there are risks that other, undetermined threat agents may be present that were not tested for. Where possible, samples or items should be treated or sterilized by methods that are universal in their inactivation of biological compounds, e.g., 0.5% sodium hypochlorite bleach, dry heat (160°C for 2h), or autoclav-ing. Where available, infectious agents may be inactivated with irradiation or vaporized hydrogen peroxide. Inactivation may damage forensic evidence, so the submitting agency should play an active role in the decision-making process as to how the sample will be treated. Regardless of how the material is treated, there should be documentation and certification of inactivation provided so that future laboratories or agencies involved will have assurance that their staff is not being exposed to an active biological threat. In some cases, the agency may want the sample or a portion of it sent to another analytical laboratory rather than to the submitting agency. Depending on the nature of the sample, special arrangements should be made to repack the sample for safe transport. In order to preserve all trace and latent evidence, the original packing materials may also be kept with the evidence (see the section below describing shipping regulations).

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