Biological fluids and body fluid stains are valuable evidence which can be used to either associate a victim or suspect with a crime/crime scene or eliminate them from consideration. The most frequently encountered biological fluids are blood, seminal fluid, and saliva.
Safety Precautions
It is imperative when collecting or packaging biological evidence for submission to the laboratory that clean latex gloves be worn and changed often. Depending on the crime scene, shoe covers, gowns, masks, head covers, and safety glasses may also be appropriate. Body fluids, wet or dry, have been shown to carry disease. Dry stains may flake when disturbed or collected, sending minute particles airborne. These may be absorbed through mucus membranes (eyes, nose, mouth, etc.), open cuts, or chapped skin. Therefore, all biological materials and fluids must be handled with universal precautions. Wearing the appropriate protective clothing also helps minimize contamination of the evidence sample with your DNA.
General Collection Guidelines
All biological evidence should be air-dried prior to submission to the laboratory. Refrigerating the evidence will retard bacterial growth on wet material. However it will not stop the growth which can then lead to degradation of the biological material. The sooner the biological evidence is dried, the more likely useful information can be obtained from the evidence through DNA analysis.
Biological evidence should be packaged in envelopes or paper bags; NEVER in plastic bags.
During the collection, air-drying, or packaging of any body fluid stains, caution should be used to ensure that a stained area from an item of evidence does not come in contact with another stained or unstained area. This applies to outer surfaces and inner surfaces. For example, a shirt should not be folded or rolled so that a stain on the front contaminates any stained or unstained area on the back or inside of the shirt. A barrier, such as paper or cardboard should be placed on the inside of the shirt, as well as under and over the garment to prevent stained areas from coming in contact with each other.
When air drying articles stained with body fluids, place them on or over a piece of clean paper. Any debris which falls from the material onto the paper during the drying process will be collected when the paper is folded with the article prior to packaging, labeling and sealing.
Body fluid evidence can be contaminated by the crime scene officer's own body fluids. The perspiration on the officer’s hands may contaminate the cotton swabs used to collect the body fluids, or talking while collecting samples may spread the officer’s saliva on the evidence. To prevent such contamination protective clothing (i.e., latex gloves, gowns, masks, and head covers) should be worn while collecting the evidence. To avoid possible sample-to-sample contamination, change latex gloves (and other applicable protective wear) as necessary when collecting evidence.
When practicable, it is best to submit the entire item of evidence to the laboratory for evaluation. If an item has been swabbed by the agency, the laboratory will not analyze the item the swab was taken from for DNA analysis. Evidence (once packaged) should be submitted to the laboratory as soon as possible. Otherwise, the items should be stored in an appropriate secured storage location until submission to the laboratory is possible. To minimize degradation of DNA, evidence should not be stored in extreme humidity or at elevated temperatures. Dry, cool storage locations are best.
Body Fluids on Non-Porous Surfaces (i.e., bottles, cans, window, knife, firearm, body, etc.)
- Double-Swab Method: (For samples taken from non-porous objects like bottles, cans, windows, knives, firearms, etc.) A sterile swab is moistened with sterile/distilled water (WET) and the area of interest is swabbed. Using the second sterile swab (DRY) immediately re-swab the area. Let the swabs dry before packaging. Two swabs only should be collected per area of interest.
- Single-Swab Method: (For samples taken from areas of the body such as external genitalia, finger/hand swabs, neck swabs due to possible strangulation, etc.) Moisten one sterile swab with sterile/distilled water and swab the area of interest. Let the swab dry before packaging. One moist swab only should be collected per area of interest.
- Note: Double-tipped swabs and Q-tips should not be used.
- Note: Avoid scraping crusts due to risk of airborne flakes.
Swabs from an item of evidence, such as the mouth of a bottle or an area of the grip of a firearm of no value for latent print examination, can be submitted for DNA analysis while the actual item of evidence can be submitted for examination by the Latent Print or Firearms disciplines
The Forensic Biology Section no longer analyzes control swabs, therefore there is no need to collect or submit a control swab to the laboratory.
Body Fluids on Porous Surfaces (i.e., clothing, bedding, carpet, untreated wood, etc.)
Submit the air-dried item of evidence if possible. For large items (large carpets, upholstered furniture, etc.) it may be necessary to cut out the stained areas or swab the stained area with a sterile swab moistened with one to two drops of water. Saturate one swab with the stain before absorbing onto the next swab. Allow the swab(s) to air dry or place the swab(s) in a new labeled swab box for drying. It is not necessary to collect more than 2 saturated swabs for submission to the laboratory.
If cuttings/swabbings are taken from different areas on an item, package the cuttings/swabbing from each area separately. The packages from separate cuttings/swabbings of a single item may be sealed individually and then combined into a larger package.
- Note: Double-tipped swabs and Q-tips should not be used.
- Note: Avoid scraping crusts due to risk of airborne flakes.
The Forensic Biology Section no longer analyzes control swabs, therefore there is no need to collect or submit a control swab to the laboratory.
Sexual Assault Evidence Collection Kit (SART kit or SAK)
A kit used for the recovery of physical evidence from the body of the potential victim or suspect of an alleged sexual assault. A specialized kit exists for pediatric victims. The kit contains supplies to recover foreign secretions and trace evidence (i.e., hairs) from the body. In addition, the kit contains supplies for the collection of a known sample from the individual for comparison with the foreign secretions and hairs. Kits are supplied by the laboratory and may be requested via an e-mail to DPS.supply.orders@alaska.gov.
The laboratory may be able to recover foreign DNA from a female victim up to 7 days after the event. Personnel are urged to follow the instructions supplied with the kit and to complete all portions of the kit paperwork. The forensic history in particular, is essential to laboratory scientists during their analysis.
***Laboratory supplied kits should be used even when collecting only penile swabs or hand swabs and a reference sample from an individual. These samples should not be submitted as separate items when they are collected as part of a sexual assault investigation.
DO NOT USE SART KITS FOR ANY PURPOSE OTHER THAN THE COLLECTION OF SEXUAL ASSAULT EVIDENCE.
Condoms
Used condoms should be air dried and submitted to the lab for processing. When the condom contains a volume of liquid, place two (or more if needed) sterile swabs in the condom to absorb the liquid. DO NOT pack the condom with gauze or paper towels. Allow the outer surface of the condom to air dry and package in a sealed envelope for submission to the lab. The lab will not routinely analyze unused condoms.
Contact DNA Evidence
Submit the item of evidence (preferred) or take a swabbing of the evidence with a single sterile cotton swab that has been slightly moistened with one (1) to two (2) drops of water. Allow the swab to air dry or place the swab in a new labeled swab box for drying. A single swab is recommended for collection to concentrate the foreign DNA that may be present and to increase the likelihood of collecting sufficient biological material to obtain a DNA profile.
- Note: Double-tipped swabs and Q-tips should not be used.
When an item requires both latent print and DNA analysis, biological screening is typically done prior to latent print examinations. Typically, smoother items (blades, slides of guns, etc.) are better for latent print recovery and textured surfaces (grips, handles, etc.) are better for contact DNA recovery. Some items are better suited for one examination or the other and will not have both types of processing performed, even when requested. The following items will not routinely have both contact DNA and latent exams conducted:
- Casings/bullets – only latent print examination will occur
- Condom wrapper – only latent print examination will occur
- Unopened beverage containers – only latent print examination will occur
- Beverage containers likely drank directly from – both exams are possible. If probative findings are obtained from either latent prints or DNA, the other analysis will generally not be performed
- Cigarette packages – only latent print examination will occur
- Cigarette butts (smoked) – only DNA analysis will occur
- Unsmoked cigarettes – neither examination will occur
Known/Reference Buccal Swabs
Buccal swabs are collected by taking two (2) sterile cotton swabs and swabbing the inner cheeks of the mouth. The swabs should be rotated during the collection process to maximize collection of cells. Let swabs dry then place both swabs together into one labeled envelope. It is not necessary to collect separate samples from the left and right inner cheeks. This is considered all one sample.
Reference samples should be collected from all persons suspected of involvement in an investigation, who may be contributors of biological evidence. These samples are part of the SART kit, but must be collected separately for persons on whom a SART kit has not been collected. The laboratory will provide swabs specifically for collecting known samples that are not part of a SART kit collection. Requests for swabs should be sent to DPS.supply.orders@alaska.gov.
“DNA on file” with the DNA database (CODIS) is NOT an acceptable substitute for an evidentiary known sample with a proper chain of custody. Known/reference samples should be collected for each separate criminal investigation that an individual is associated with. These samples should be submitted along with other evidentiary material to ensure that laboratory testing is not suspended pending receipt of known samples.
DNA Database Collection Kit
These kits are exclusively for use in collecting the statutorily mandated samples from arrestees and convicted offenders as per AS44.41.035. The kit contains instructions for the proper collection of the samples (buccal swabs and thumb prints) and completion of the information card. Kits can be obtained by e-mailing DPS.supply.orders@alaska.gov. DO NOT USE DATABASE COLLECTION KITS FOR ANY PURPOSE OTHER THAN THE COLLECTION OF CONVICTED OFFENDER AND ARRESTEE SAMPLES.
Products of Conception (for Criminal Parentage Investigations)
Tissue collected from an aborted fetus that is 10 to 12 weeks old may contain identifiable body characteristics (i.e., hands and feet) that can easily be isolated by the DNA analyst for testing. If the fetus is less than 10 weeks old, the body characteristics may not be easily identified by the examiner.
When possible, request the medical doctor to isolate a portion of the fetal tissue from the maternal tissue and place the fetal tissue into a hard plastic container (i.e., specimen cup). Alternatively, the entire aborted fetal material may be submitted.
- Note: The fetal tissue/material should not be stored in a saline solution or any other type preservative.
Submit the container to the laboratory the same day. If it is not possible for the aborted fetal tissue/material to be submitted to the laboratory the same day, place the container into a refrigerator and submit to the laboratory the next day. When submission cannot be achieved within 24 hours, the sample should be frozen. Within a short period of time fetal tissue/material stored in plastic, even if refrigerated will promote bacterial growth, which can destroy biological material and potentially preclude the examiner from obtaining DNA results.