Storage: Non-toxicological Biological Evidence

Because moisture can cause biological material to be destroyed by bacterial growth, non-toxicological biological evidence shall be thoroughly dried prior to packaging and storage unless: (a) It is not possible to dry the evidence as is (e.g., a tube of liquid blood). In this case, it is acceptable to retain a sample of the blood on a medium such as FTA™ paper that is suitable for long-term storage conditions and discard the remainder of the sample. (b) If evidence cannot be dried or stored on alternate media such as tissue samples, bone, liquid urine, or blood, the evidence shall be stored in impermeable, nonporous, airtight containers and frozen. Glass containers shall never be used for packaging, as freezing can cause the vial to explode or crack. Breathable (porous) containers which minimize the retention of potentially damaging moisture shall be utilized for the storage of non-toxicological biological materials. Breathable containers include, but are not limited to, previously unused paper bags, glassine envelopes, coin envelopes, butcher paper, and cardboard boxes. (For additional information on packaging, refer to Page 16 of the NIST Biological Evidence Preservation Handbook.) (3) Evidence containing non-toxicological biological material shall be stored under conditions that reduce the rate of bacterial growth and the degradation of DNA. Depending on the nature of the evidence, acceptable conditions may include refrigeration, freezing, or in a temperature controlled environment. (Refer to Table 111-1 and Table 111-2 of the NIST Biological Evidence Preservation Handbook for specific information regarding the storage options.) (4) At no time shall non-toxicological biological evidence be stored in environments where the potential for large temperature and humidity fluctuations outside of the ideal range exists . (5) Conditions of non-toxicological biological evidence storage shall, at a minimum, include protection from moisture, excessive heat, and sunlight.