U.S. flag

An official website of the United States government, Department of Justice.

Collecting DNA Evidence at Property Crime Scenes

Blood and Body Fluid Collection

Blood and Body Fluid Collection

The most common methods used to collect blood and body fluid evidence include the following:

Image of using a clean cutting device to remove a section of carpet containing a stain
National Institute of Justice (NIJ) (see reuse policy).
  • Cuttings. Remove a section of the item containing the stain using a sterile or clean cutting device.
     
  • Wet absorption. A sterile swab, gauze pad or threads slightly moistened with distilled water. Concentrate the stain in a localized portion of the swab or pad. When a swab is used, the stain should be concentrated on the tip. The collection medium is pressed or rubbed into the stain and allowed to air-dry. Some laboratories recommend following the first moistened swabbing with a second dry swabbing to ensure thorough sample collection. Both swabs are retained and submitted for analysis.
     
  • Scraping method. The sample in the video below is scraped with a clean razor blade or scalpel, into a clean piece of paper that can be folded and packaged in a paper envelope. This is a method to be used in a controlled environment (i.e., no wind or traffic) and where the scrapings will not contaminate other evidence." with this text "Scraping method. The sample is scraped with a clean razor blade or scalpel, into a clean piece of paper that can be folded and packaged in a paper envelope. This is a method to be used in a controlled environment (i.e., no wind or traffic) and where the scrapings will not contaminate other evidence.  This method is rarely used on scene.

    Open and save a double sided printable version of bindle paper.
     

     

  • Tape-Lifting method. An optional method for collecting dried blood stains on a nonabsorbent surface is using fingerprint tape. The fingerprint-lifting tape may be placed over the stain and lifted off. The stain is transferred to the adhesive side of the tape, which may then be secured on a clear piece of acetate for submission to the laboratory. Note: When using this method, the collector must ensure the fingerprint tape is not contaminated with other biological materials.

Back Forward