Safety & Contamination

Impounding Officer

Blood Evidence

Moist Blood, Large

Moist Blood, Small

Dried Blood



Rape Kits

Booking Procedure

Evidence Officer Procedure





AIDS has a short life span when exposed to air.  However, HEPATITIS can live for years in the open air.  Hepatitis contaminated evidence has been frozen and thawed years later.  The virus was shown to still be alive.




General Information

Biological fluids such as blood, semen, and saliva are frequently encountered as physical evidence in many types of criminal investigations such as homicides, sexual assaults, assaults, and robberies.


Since blood, semen, and saliva originate as liquids, they quickly coat or penetrate surfaces they are deposited on, and when dried they are difficult to remove.  Because no two humans are genetically the same (except for identical twins) these body fluids are unique to the person they originated from. By performing DNA analysis of these fluids or stains, a genetic marker profile can be obtained that is essentially specific to that individual.


Because DNA analysis lends itself to a computerized identification system, a Convicted Offender Database has been established which allows the forensic laboratories to enter DNA profiles from evidence samples for comparison to the DNA profiles obtained from other unsolved crimes or from convicted violent offenders. This database is one of the latest forensic technologies aiding in the identification of suspects in cases where no suspect has been developed.


The type of DNA analysis currently performed on biological material can yield much information. The table below lists those things that DNA analysis can determine and those it cannot.


DNA analysis can:

DNA analysis cannot:

Associate evidence DNA to a person and give the frequency of occurrence in a random population

Determine the age or race of the person who donated the sample

Positively exclude a person from being the donor of evidence DNA

Determine how old the sample is

Determine the gender of an evidence DNA donor

Determine how the sample was deposited (see “Crime Scene Investigations – Bloodstain Pattern Analysis”)

Determine that the biological material is from a human

Determine whether or not force was used in a suspected rape from the analysis of semen evidence


Safety and Contamination Prevention

Current DNA technology allows for very small amounts of sample to be analyzed. For example, a blood stain the size of a sharpened pencil point may be enough to perform DNA analysis on, as would the residue amount of sweat and skin cells on the inside rim of a ball cap. Because of this, inadvertent contamination of the evidence is possible if you do not take precautions.


General Collection Guidelines

In general, wet or moist biological evidence should be dried if possible and packaged into paper containers. Paper packaging prevents the evidence from degrading, so wrapping the evidence first in plastic then placing that inside paper (or vice versa) defeats the purpose. Mark the packaging with a “BIOHAZARD” label.


Rules of thumb for long-term storage of biological evidence is refrigerate wet or liquid evidence and freeze dry evidence.


UV Light Searches

Many officers chose to use an ultraviolet (UV) light, Woods lamp, or other alternate light source to assist in the search for biological stains. Such devices can be helpful in a search, given that many biological stains such as semen and saliva may fluoresce, or appear bright, when viewed with UV light in a darkened room.  However, there are three important points to remember when using a UV light to assist your search for biological stains:

  1. A number of other materials may also fluoresce, such as urine, stains from food or drink, laundry detergent, and many other substances.

  2. Not all semen or saliva stains will necessarily fluoresce with a UV light.

  3. Blood will not fluoresce when viewed with a UV light; rather, it will appear dark.


Blood Evidence

Blood evidence is common in violent crimes. In addition to DNA, blood contains cells and proteins that allow the laboratory to perform the following examinations:

  1. Testing can determine if blood is human or non-human in origin.

  2. The specific animal family can be determined for non-human blood.


Collecting Liquid or Moist Blood – Large Quantity

  1. Saturate several (5 to 10) sterile cotton swabs with the blood. Allow swabs to air-dry.

  2. Venous blood will coagulate so it is important to collect a good mix of clotted cells and serum.

  3. The dried swabs can be placed in a paper container (e.g. paper envelope or bag).

  4. Do not lick envelope seals, as this is a safety and contamination hazard.

  5. Swabs can also be placed in a pipette to protect sample while drying (see photo below).

  6. Once dry the swab and pipette can be placed in a paper envelope.


Collecting Liquid or Moist Blood – Small Quantity

  1. For each separate blood drop, stain or smear, the investigator should use only one blood swab to collect a sample.  One-by-one, use swabs to collect the blood, concentrating the blood onto each swab.

  2. Allow swabs to air-dry.

  3. The dried swabs can be placed in a paper container (e.g. paper envelope or bag).

  4. Properly label and seal the container. Do not lick envelope seals as this is a safety and contamination hazard.


Collecting Dried Blood

If the stained object is transportable, submit the item intact. Dried blood may flake off an object, so be careful to seal all openings of a package. If it is not transportable, collect the blood by one of the following methods.




  1. Moisten a sterile cotton swab using distilled water or tap water (if using tap water collect a separate sample of just the water).

  2. Shake the swab to remove excess water.

  3. Gently swab the stain with the moistened swab tip until the swab thoroughly absorbs the blood. Continue collecting the stain until it is either completely collected or a sufficient number of swabs (at least 4-6) have been saturated.

  4. Allow the swabs to thoroughly air-dry.

  5. The dried swabs can be placed in paper container (e.g. envelope, paper bag) and sealed.

  6. Select an unstained area adjacent to the suspected bloodstain and collect a sample in the same manner as described above. This sample will serve as a negative control.


Cut out the stain

This may be desirable when the dried bloodstain is on an object such as the upholstery of a car seat or on carpeting. Use a clean, sharp knife or scissors to excise the stained area. Include areas that are unstained in your cutting for use as a negative control. Package into a paper envelope and seal.


Remember that you may be liable any time you destroy property.


Saliva Evidence

Saliva stains are not usually evident from a visual examination. However, certain types of evidence frequently contain traces of saliva (e.g. cigarette butts, gummed surfaces of envelopes, chewing gum, bite marks, ski and/or nylon masks, etc.).


Collecting Saliva Evidence

If the stained object is transportable, submit the item intact. If it is not transportable, such as bite marks on a body, collect the saliva stain in the following manner:

  1. Moisten a sterile cotton swab with distilled or tap water.

  2. Shake the swab to remove excess water.

  3. Gently swab the suspected saliva stain.

  4. Allow the swab to thoroughly air-dry prior to packaging in a paper envelope and seal.

  5. Select an unstained area and collect a sample in the same manner as described above. This swab will serve as a negative control.

Semen Evidence

When the perpetrator of a sexual offense is a male, semen stains may be found on the victim as well as on clothing, bedding, rags, upholstery and other objects.


Collecting Semen Evidence

  1. Carefully recover all suspected stained material. Each item of evidence should be packaged separately and carefully to prevent loss of any trace evidence that may be present and to prevent cross-contamination.

  2. Air-dry all damp stains. Consider marking the location of a damp stain on the evidence itself, as it may not be visible when dry.

  3. Clean paper should be spread under the item to catch any debris, which may be dislodged during the drying process, and between items hanging next to each other to prevent cross contamination. Package each item separately in paper bags or envelopes, along with any paper used.

  4. If the semen stain is on an object that cannot be easily submitted to the laboratory, request forensics staff to recover the stain.



  1. When blood is seized, the investigator should use the  following stopper colors:

  1. BAC - gray

  2. Blood for typing -red

  3. Blood for DNA - purple

  1. Clothing and bedding, which contain body fluids, will be placed in fiber bags for transportation to the Evidence Processing Room.  (Fiber bags are available in the senior deputy/corporal cars).  Consideration should be given to placing the fiber bag into a plastic bag for transportation.

  2. If a plastic bag is used, log the item into evidence.

  3. If liquid (urine or blood in a vial), it must be refrigerated.  Seal the vials or containers in a Secure-Pak box.  Submit into evidence locker #1 (the refrigerator) individual locked box.

  4. Keep urine containers and blood vials in separate containers.

  5. Any item, such as swabs, clothing, or anything that may contain body fluids shall be air dried prior to packaging. 

  6. Complete the evidence tag and attach it to the packaging.  Attach a Bio-Hazard sticker to all items of evidence that may contain body fluids.

  7. Complete the Forensic Services Report, place blue & yellow copies in basket in Evidence Processing Room.

  8. Complete the property-evidence report.

  9. Place the properly packaged evidence into the appropriate location.  Note the location on the property-evidence report.

  10. Place wet items containing body fluids in locker ‘A’ and ‘B’ in the Law Enforcement Center and do not package.  Refer to Clothing (impounding officer #2) for additional information. 

  11. Select the correct size bag(s) for packaging, complete and attach the evidence tag.  Leave the packaging in the locker with the items to be packaged.  (If there is a chance that the packaging will become wet, leave it (packaging) with an evidence  officer, or in another locker.

  12. Do not co-mingle victim/suspect clothing within the same locker.

  13. Place the yellow and green copy of the property-evidence report in the property-evidence basket in the Evidence Packaging Room.




  1. After items containing body fluid have dried, the evidence officer shall further package the items.

  2. Place one barcode on the item and the corresponding barcode on the property receipt.

  3. Place the item in a location best suited to the item, and area specified by the evidence room guide, see Evidence Room Map.

  4. Physiological evidence with a potential to be used for DNA testing should be stored in the designated biohazard area or placed into the freezer.

  5. Liquid blood (such as samples in test tubes) should only be refrigerated.

  6. Items with bloody fingerprints should not be refrigerated or frozen (this can destroy the prints).

  7. Using the barcode reader, scan the bin location, and then scan the barcode that is affixed to the item.

  8. Place the item in numerical order within the bins in the refrigerator and freezer by case number.




AIDS has a short life span when exposed to air.  However, HEPATITIS can live for years in the open air.  Hepatitis contaminated evidence has been frozen and thawed years later.  The virus was shown to still be alive.





  1. Upon disposition request authorization from investigating officer.

  2. Upon expiration of Statute of Limitation, request authorization from investigating officer.

  3. Release the item to the owner IF APPROPRIATE.

  4. Biohazards not released to owners will be disposed of in an appropriate biohazard bin.  Items too large for an onsite biohazard bin will be destroyed at the Marion County Waste Management. (See destruction item 2-9)



DO    air dry items but keep from fans or extreme heat.  Fans may dislodge trace evidence.

DO    submit entire items with suspected blood stains to the laboratory if possible.

DO    obtain oral swab standards from all involved persons

DO    refrigerate specimen(s) containing liquid blood.  All other items may be kept in storage at room temperature and

          low humidity.

DO    mark package with biohazard warning symbol and label.

DON’T submit partially dried objects since decomposition will occur.

DON’T put stained items into plastic bags, vials, or other airtight containers.

DON’T attempt to remove stains from cloth or from small solid objects.

DON’T mix separate dried stains.  Package each individual item in a paper bag or box, seal and label.

DON’T place evidence in the trunk of a car since extreme heat may make

             blood unsuitable for testing.

DON’T freeze liquid blood standards.

DON’T allow specimens to be exposed to direct sunlight.



During investigations when there is cause to believe that an individual may have been under the influence of alcohol and/or drugs, efforts should be made to obtain blood and/or urine for toxicological analysis. In cases where it is necessary to determine the level and effect of alcohol on the individual, blood is the specimen of choice. Urine may be tested for the presence of alcohol, however it is not a legally recognized testing medium for blood alcohol determinations and therefore a percentage of alcohol will not be reported. In cases where the use of controlled substances or other drugs is in question, urine is the specimen of choice.


Time is of the essence when examining blood for the presence of drugs; many drugs leave the blood very rapidly and may be difficult to detect or may yield negative results. Drugs are in greater abundance in urine and therefore more readily screened for than blood. When there is a question as to which medium is best, collect both blood and urine. 


Blood Alcohol

The State crime laboratory no longer recommends the collection of sequential blood draws. Testimony given at the time of trial will be exactly the same whether there is one blood draw or many.


***Normally, the laboratory will not test blood for alcohol content if a breath test has been administered***


Collection, Packaging, and Storage

At least 10 milliliters (one tube) of blood should be collected in a commercially available gray-top tube that contains sodium fluoride and potassium oxalate or EDTA. Blood Alcohol Specimen Kits can be purchased for packaging and securing the blood tube. Contact the state crime laboratory to order these kits.


Per OAR 333.13.026 (2)(c) a specimen labeling system must be employed which assures unequivocal matching of the specimen with the person from whom it was collected.  The tube must be labeled with the individual’s name, date, and time of the blood draw. Care should always be taken to maintain proper chain of custody by the sealing and labeling of evidence.  Hospital staff must use a gray stopper on the blood vials.


Blood should be submitted to the state crime laboratory as soon as reasonably possible.  Otherwise the blood sample should be refrigerated.  If the crime lab attaches a label with storage recommendations, be sure they are followed.  If no label is attached, the sample can be stored per Sheriff’s Office  normal evidence handling procedures.



  1. Quantitation of the amount of drug(s) in a urine sample is not performed because urine drug concentrations cannot be correlated to a level of impairment.

  2. Include suspected drug information and consider a drug recognition evaluation by a drug recognition expert (DRE) in conjunction with obtaining a urine sample. 


Drugs Tested in Routine Toxicological Analysis

Opiates (e.g. morphine, codeine, etc.)

Amphetamine-like drugs (e.g. amphetamine, methamphetamine, MDMA, etc.)


Benzodiazepines (e.g. Valium, Librium, etc.)



Other basic drugs (e.g. methadone, antihistamines, etc.)


Other pharmaceutical drugs (e.g. Prozac, Soma, etc.)


Collection, Packaging, and Storage

Urine Collection Kits are provided by the Oregon State Police and should be available at all intoxilyzer locations. These kits can also be obtained through the OSP stockroom by calling 503-378-4348.


Urine samples should be collected in the plastic screw-top container provided in the kit.  Be sure the lid is tightly secured, and seal and label the container with the individual’s name, date, and time the sample was collected, making note of the temperature of the urine specimen.


Secure the urine cup in the plastic bag provided to contain any possible leaks, and then put the bag in the box.  It should be noted that urine that leaks into the plastic bag may not be analyzed.  Urine should be submitted to the state crime laboratory as soon as reasonably possible. Otherwise the urine sample should be refrigerated.  Urine evidence returned by the crime laboratory should be stored  as indicated on the attached label. If no label is attached, the sample can be stored per Sheriff’s Office normal evidence handling procedures.


If you suspect a date rape drug (e.g. GHB, Rohypnol, ketamine, etc.), inhalants (e.g. paint thinner, gasoline, etc.), or LSD were used, this must be specifically noted on the Forensic Services Request. These drugs are not routinely tested for in a toxicology analysis.


Revised 04/25/07