BIOLOGICAL EVIDENCE

Storage Conditions

Note: Guidance on additional biological evidence types and full citations can be found in the full text version of

The Biological Evidence Preservation Handbook ( http://www.nist.gov/manuscript-publication-search.cfm?pub_id=913699 ).

Short-Term Storage: Storage of evidence from the time collected to 

reception by property room personnel. The Working Group recommends 

that temporary or short-term storage refer to any location that can hold 

evidence for up to 72 hours. 

Long-Term Storage: A location that is designated to secure evidence 

or property items in the custody of an agency until the items are diverted, 

sold, released, or destroyed. The Working Group recommends that long-term 

storage refer to any location where evidence may be stored for more than

72 hours.

Frozen: A storage condition in which the temperature is maintained 

thermostatically at or below –10°C (14°F). 

Refrigerated: A storage condition in which the temperature is 

maintained thermostatically between 2oC and 8oC (36oF and 46oF) with less 

than 25% humidity.

Temperature Controlled: A storage condition in which temperature is 

maintained thermostatically between 15.5°C and 24°C (60°F and 75°F) with 

less than 60% humidity.

Room Temperature: A storage condition in which the temperature is 

equal to the ambient temperature of its surroundings; storage area may lack 

temperature and humidity control methods.

Key definitions

Sources: Liquid Blood—Farkas et al. 1996; Austin et al. 1996; Visvikis, Schlenck, and Maurice 2005; Gino, Robino, and Torre 2000; Ross, Haites, and Kelly 1990. Urine—Gino, Robino, and Torre 2000; Prinz, 

Grellner, and Schmitt 1993; Benecke 2004; Elliott and Peakman 2008. Dry Biological Stained Items—Gino, Robino, and Torre 2000; Kobilinsky 1992; Lund and Dissing 2004; Sjöholm, Dillner, and Carlson 

2007; Aggarwal, Lang, and Singh 1992. Wet Bloody Items—Kanter et al. 1986. Bones—Kobilinsky 1992. Hair—Steinberg et al. 1997. Vaginal Smears—Gill, Jeffreys, and Werrett 1985. Feces—Benecke 2004. 

Buccal Swabs—Steinberg et al. 1997; Sigurdson et al. 2006.

Short-Term storage conditions

Type of Evidence Frozen Refrigerated Temperature Controlled Room Temperature

Liquid Blood Never Best Less than 24 hours

Urine Best Less than 24 hours

Dry Biological Stained Item Best Acceptable

Wet Bloody Items

(if cannot be dried) Best Acceptable Less than 24 hours

Bones Acceptable Acceptable Acceptable

Hair Best Acceptable

Swabs with Biological Material Best (wet) Best (dried)

Vaginal Smears Best

Feces Best

Buccal Swabs Best Less than 24 hours

Sources: Liquid Blood—Farkas et al. 1996; Austin et al. 1996; Visvikis, Schlenck, and Maurice 2005; Gino, Robino, and Torre 2000; Ross, Haites, and Kelly 1990. Urine—Gino, Robino, and Torre 2000; Prinz, 

Grellner, and Schmitt 1993; Benecke 2004. Dry Biological Stained Items—Gino, Robino, and Torre 2000; Kobilinsky 1992; Lund and Dissing 2004; Sjöholm, Dillner, and Carlson 2007; Aggarwal, Lang, and 

Singh 1992; McCabe et al. 1987; Kline et al. 2002. Bones—Kobilinsky 1992. Hair—Steinberg et al. 1997. Vaginal Smears—Gill, Jeffreys, and Werrett 1985. Feces—Benecke 2004. Buccal Swabs—Steinberg et 

al. 1997. DNA Extracts—Yates, Malcolm, and Read 1989; Dissing, Søndervang, and Lund 2010; Halsall et al. 2008; Kline et al. 2002; Sigurdson et al. 2006.

Long-Term storage conditions

Type of Evidence Frozen Refrigerated Temperature Controlled Room Temperature

Liquid Blood Never Best

Urine Best

Dry Biological Stained Items Best

Bones Best

Hair Best Acceptable

Swabs with Biological Material Best (dried)

Vaginal Smears Best

Feces Best

Buccal Swabs Best

DNA Extracts Best (liquid) Acceptable (liquid) Acceptable (dried)

Te c h n i c a l Wo r k i n g G r o u p o n B i o l o g i c a l E v i d e n c e P r e s e r v a t i o n

National Institute of

Standards and Technology

U.S. Department of Commerce

National Institute of

Standards and Technology

U.S. Department of Commerce