Sample Storage

Work and storage space must accommodate sample accessioning and processing, including sufficient bench space and safety hoods. An estimate of the number of potential samples should be made so that sufficient storage space can be assured (see exhibit 4, Estimated DNA Analysis Workload Worksheet). Soft tissue samples need to be stored in ultra-low-temperature freezers. In addition to securing appropriate freezer space, additional refrigerators may be needed to store samples during the extraction and analysis phases. If sample recovery at the disaster site is a long-term process, tissue decomposition will become a factor in planning for sufficient storage space.

Depending on the conditions at the disaster site, larger portions of tissue may be needed to compensate for degradation as time passes during the collection process. In the case of bone, for example, a few cubic centimeters may (under optimal conditions) be adequate for analysis, but an entire femur may be required in more compromised situations. Not only do larger samples require more storage space, but extraction procedures may require modification to accommodate larger sample sizes.

Following the WTC attacks, other laboratories offered to assist the Office of the Chief Medical Examiner (OCME). Such offers are likely to occur after any future mass fatality incident. If appropriate chain-of-custody, accessioning, and other infrastructure concerns are addressed, outsourcing may be considered. Obviously, however, if samples are sent to other laboratories at any stage of the analysis, the same quality control and chain-of-custody practices must be maintained (see chapter 14, Quality Control).

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