B8. Evidence Collection

These recommendations are for pediatric examiners to facilitate collection of forensic specimens.[1]

Recognize that timely medical care for all child sexual abuse victims is of paramount importance, regardless whether forensic specimens are potentially available. Physical findings from the acute or nonacute examination should also always be documented, regardless whether forensic evidence is collected.  

Collect forensic evidence from a prepubescent child sexual abuse victim within the time frame prescribed by the jurisdiction,[2] when there is a possibility of biological or trace evidence on the child’s body, or if the timing of the abuse is unknown/not clear. In addition, case circumstances and future research may indicate a need for forensic evidence collection beyond that time frame. (See A5d. Timing of Evidence Collection and B3. Entry into the Health Care System) Forensic specimens obtained during the medical forensic examination may be helpful in criminal justice, family, and/or juvenile justice proceedings that result from the report of sexual abuse. A standardized forensic evidence collection kit is recommended to collect forensic samples, as per jurisdictional policy. (See A5c.Evidentiary Kits and Forms)

Seek as much forensic evidence as possible, guided by the medical history, information from investigative agencies, examination findings, and the children’s assent to procedures. What forensic samples are collected may vary depending on details obtained during the medical history and input obtained via the initial report or forensic interview. If any forensic evidence requested in the evidentiary kit is not collected—or collection modifications are made—note reasons on documentation forms. In the instance that a child is unable to give a clear history (which is not unusual with young children) and/or a detailed account of the abuse is not available, complete all steps of the kit. Examiners are encouraged to communicate with investigators, prosecutors, and crime lab personnel to share relevant case information and seek clarification regarding forensic evidence to collect in specific cases (as well as more generally what items to collect and the preferred collection and preservation methods).

Basic evidence collection is built on the understanding that where contact between two objects exists, there also exists the possibility of material transfer (DeForest & Lee, 1983). Any contact between a perpetrator, child, and the crime scene itself may hold corroborating evidence. This evidence may be trace materials and/or body fluids from the perpetrator. During medical forensic care, forensic samples should be taken from areas of the child’s body where evidence may exist. Clothing, especially underwear, and linens are the most likely positive sites for evidentiary DNA in prepubescent children (Christian et al., 2000; WA, 2012). Investigating agencies may also look for evidence on other items from the child’s home and scene of abuse. Information derived from analysis of biological and trace evidence may help determine if sexual contact occurred, provide data regarding the circumstances of the incident, and be compared to reference samples collected from children and suspects for identification purposes.

Be familiar with general forensic considerations, as outlined below. However, follow facility and jurisdictional policies as applicable.

General Forensic Considerations



Take precautions during the examination to prevent patient/health care staff exposure to blood borne pathogens and other potentially infectious materials.

Follow facility policies on washing hands, handling contaminated needles and other contaminated sharps, wearing protective equipment, and minimizing splashing, spraying, and spattering of infectious materials. Exam room and nondisposable equipment should be cleaned per facility policy between patients.

Wear gloves throughout the forensic evidence collection process. Also, change gloves frequently when examining different body areas.

Changing gloves between different collection points prevents possible contamination of specimens and exposure to blood/body fluids, as well as cross contamination. Due to the sensitivity of evolving DNA testing methods, it is important to stay current on additional measures to avoid contaminating specimens (e.g., wearing a mask and limiting talk during the collection of specimens).

Collect forensic evidence as soon as possible.

The likelihood of obtaining viable forensic specimens decreases over time. (See A5d. Timing of Evidence Collection)

When collecting specimens for both medical testing and forensic samples, collect forensic samples first.

There is an increased likelihood of obtaining biologic materials with the first specimens collected.

Handle specimens appropriately after collection. Ensure security of specimens. Limit the number of persons who handle forensic evidence.

Ensure that specimens are properly dried, packaged, labeled, sealed, and stored. Properly maintain and document chain of custody of forensic evidence. Procedures should be in place so that evidence is properly transferred to law enforcement personnel. (See A5e. Evidence Integrity)

Keep medical specimens separate from forensic specimens.

It is not necessary to maintain the chain of custody of medical specimens.

Specimens collected for medical purposes should be kept and processed at the health care facility, as per facility policy. Specimens collected for forensic analysis should be transferred to the crime laboratory or other specified laboratories (e.g., a toxicology lab) for analysis, as per jurisdictional policy.

Do not put toxicology samples in the evidence collection kit, unless otherwise indicated.

Maintain the chain of custody of toxicology samples.

If toxicology samples are collected, they may be analyzed at a different location than other forensic specimens. If that is the case, identify which labs the jurisdiction has selected to analyze these samples; choose a lab, if more than one option exists; and follow its policies for sample collection, preservation, and transfer. (See B9. Sexual Abuse Facilitated by Alcohol and Drugs)

Collect forensic samples according to jurisdictional policy. The table below provides general guidance on the collection of common forensic samples. Jurisdictions may require collection of additional or different specimens and may use different collection methods (e.g., number of swabs used to collect a specific sample). It is important to follow jurisdictional policies regarding what specific forensic samples to collect for different types of sexual abuse, and when, with what, and how to collect each specimen. This instruction is usually included in jurisdictional evidentiary kits. Consult with the crime lab if questions arise.

As noted in A5e. Evidence Integrity, forensic specimens should be adequately dried where possible to prevent degradation, and packaged in material that will not retain moisture (e.g., paper versus plastic).

Follow jurisdictional policies, and toxicology lab policies as applicable, for drying and packaging forensic samples, as well as for packaging evidence that cannot be dried thoroughly at the exam facility. With wet evidence, the goal is to preserve that evidence while preventing leakage and contamination of other evidence. Dried specimens generally do not require refrigerated storage; wet items generally need refrigeration. Also, to maintain the integrity of forensic samples, it is critical to properly label, seal, and document the chain of custody during specimen collection through their release to law enforcement.[3]

For children with disabilities who utilize assistive devices (e.g., motorized wheelchairs and telecommunications equipment) and/or service animals: If either is considered as forensic evidence in a case, they can be swabbed and photographed, with the same intent and process used to collect and photo-document evidence from the body. They should not be taken away from the child. (See B2. Initial Response)

Guidance on Common Forensic Sampling

Forensic Sample and Type/Nature of Abuse

Possible Material and Timing of Collection

Supplies and Sampling Instructions

Label/seal as per jurisdictional policies

Sample: Oral swabs[4]


When there may have been genital/oral penetration with or without ejaculation

Seminal fluid if oral penetration


Timing: Continuous rinsing of the mouth with saliva and acts of eating and drinking fluid will limit the amount of DNA in the sample.[5]

Sterile cotton-tipped swabs


· Use two dry swabs to swab/rub over the oral cavity (e.g., under tongue, around teeth, cheeks, and gums).

Sample: Buccal swabs


In all cases of forensic evidence collection


Patient reference DNA sample[6]


Note: Use buccal swab as the reference sample unless it is absolutely medically or forensically necessary to take blood. For example, in the case of recent oral penetration, a blood sample might need to be considered to avoid contamination (De Jong, 2011).

Sterile cotton-tipped swabs


· Use two swabs to swab/rub over the inner aspect of each cheek.

· Collect the buccal swab as the patient DNA standard after the oral swab is obtained—rinse mouth after the oral swab is obtained and before collection of the buccal swab (De Jong, 2011).

Sample: Blood


Only if alcohol- or drug-facilitated sexual abuse is disclosed or suspected




If buccal swab is not acceptable for reference DNA sample[7]

Presence of alcohol/drugs in blood


Timing: Collect if ingestion of alcohol or drugs used to facilitate sexual abuse may have occurred within 24 hours prior to the exam or if time of ingestion is uncertain (Society of Forensic Toxicologists [SOFT], n.d.).


Note: Due to potential emotional trauma to the child, avoid taking blood samples unless absolutely necessary. If collected, use the most noninvasive methods (Ohio Chapter of the AAP Committee on Child Abuse and Neglect, 2009).

For toxicology sample:


Alcohol-free prep pad/betadine swab


Gray-top tube (contains preservatives sodium fluoride and potassium oxalate) or as per jurisdictional policy


Pediatric needle and blood tube as needed


· Check expiration date on the tube and replace, if expired.

· Collect the maximum amount of venous blood allowable by weight of child per blood draw.[8]

· Refrigerate when stored, as per toxicology lab policy.

Sample: Urine


If alcohol- or drug-facilitated sexual abuse is disclosed or suspected


Presence of alcohol or drugs in urine


Timing: Collect if ingestion of alcohol or drugs used to facilitate sexual abuse may have occurred within 120 hours prior to the exam (SOFT, n.d.; United Nations [UN] Office on Drugs and Crime, 2011).

Appropriate sterile container with at least 1.5% sodium fluoride preservative


· Collect as soon as possible after the event as drugs are quickly eliminated from body.

· If collecting specimen prior to other evidence collection, instruct not to wipe (Massachusetts Department of Public Health, 2005).

· Collect a minimum of 30 mL of urine (up to maximum amount that can be obtained).

· Refrigerate or freeze when stored, as per toxicology lab policy.

Sample: Fingernail swabs


If the patient broke a fingernail during abuse or scratched or dug at the body of the assailant

Skin, blood, saliva, fibers, etc. (from assailant); and for comparison with any broken nails found at the crime scene


Note: Prior to taking fingernail specimens, photograph fingernail damage that may have been related to the abuse.

Sterile cotton-tipped swabs × 2


Sterile water


· Moisten first swab with water and clean under fingernails; repeat with the second dry swab (two swabs for each hand).

· Only collect fingernail clippings if a nail was broken during the abuse.

Sample: Clothing


If the patient is wearing the same clothes as at the time of the abuse (even if they have been washed)


If the patient has changed clothes since the abuse, collect underpants only (if underpants are worn)


Clothing worn during or immediately after the abuse may also be brought to the examination rather than worn by the child.

Adherent foreign material (e.g., semen, blood, hair, saliva, and fibers from or touched by the assailant and/or from the crime scene)


Note: Although foreign matter can be washed or worn off the body, the same substances may be found intact on clothing for a considerable length of time following the abuse. There may also be alternations to clothing as a result of the abuse (e.g., a rip or loss of a button).


Note: Carefully evaluate the need to take coats and shoes, as loss of these items may represent a financial burden to the child’s family. If necessary, the exam facility, in coordination with victim advocacy program, may be able to offer replacement clothing.

Paper bags


Collection paper


· Follow jurisdictional policies for collection of clothing items.

· Each piece of dry clothing and collection paper used should be placed in a separate paper bag.[9]

· Follow jurisdictional policies for packaging items too wet to dry at the exam facilities and for refrigerated storage.

Sample: Diapers, pull-ups, or other absorbent padding, condoms


If the patient was wearing a diaper or padding of any kind at the time of the abuse or immediately following


If a condom is found in or on the patient’s body from the abuse


These items may also be brought to the examination rather than worn by the child.

Body fluids/DNA or other foreign material (e.g., semen, blood, hair)

Materials as per jurisdictional policy


· Collect these items if used during or after touching or any genital copulation. Dry, package, and submit as per jurisdictional policy.

· For condoms: Collect, dry, and package as per jurisdictional policy, noting drying and packaging techniques that are recommended by crime labs can differ (Technical Working Group on Biological Evidence Preservation, 2013).

· Follow jurisdictional policies for packaging items too wet to dry at the exam facilities and for refrigerated storage.

Sample: Other body surface swabs and specimens


If there are areas on the skin where saliva, semen, or other bodily fluids from assailant may have been deposited (e.g., around the mouth in the case of oral abuse), or the assailant may have touched


If foreign material or debris is seen, collect specimen[10]

Body fluids/DNA; other possible foreign materials, such as vegetation, matted hair, or foreign hairs[11]


Note: Use of an ALS may help guide collection of swabs. (See A4c. Equipment and Supplies)


Note: Debris and the assailant’s body fluids/DNA could also be found on equipment used by patients with physical impairments, such as wheelchairs, scooters, canes, wheelchair pads, assistive communication devices, catheters, and service animals.

Cotton-tipped swabs × 2 per site

Sterile water


· Moisten first swab with water and swab/rub over sites where semen, body fluids, or DNA may be present.

· Repeat with the second dry swab.




· Place foreign material in bindle, and enclose and seal in evidence envelope.

Sample: Swabs of female genitalia


If possible vaginal/penile penetration, other genital-to-genital contact, or contact that could have left biologic material including oral-to-genital

Body fluids/DNA; other possible foreign material






Cotton-tipped swabs


Sterile water


· Moisten first swab with water and thoroughly swab/rub over the labia majora; repeat with the second dry swab.[12] Alternately, two swabs can be lightly moistened and the sample sites swabbed simultaneously with both swabs.

· Repeat same procedure as needed per additional sample site.

Sample: Penile swabs


Penile shaft and prepuce (foreskin); glans and scrotum

If possible penile/vaginal penetration, other genital-to-genital contact, oral contact, anal or rectal contact, or foreign material disclosed or suspected (e.g., lubricant)

Body fluids/DNA; other material

Cotton-tipped swabs


Sterile water


· Moisten first swab with water and swab/rub over the shaft of the penis and prepuce/foreskin (when present); repeat with the second dry swab.

· Repeat the same procedure for the glans and scrotum, avoiding the urethra (swabs from the urethra will result in obtaining the patient’s own DNA).

Sample: Anorectal swabs (perianal and anal canal)


If possible anal/penile or rectal/penile penetration, oral/anal penetration or contact, digital/object penetration or contact by assailant, or foreign material or object

Body fluids/DNA; other material

Cotton-tipped swabs


Sterile water


· Moisten first swab with water and swab/rub over perianal area/folds; repeat with the second dry swab.

· Using another two swabs, repeat the same procedure for the anal canal.

Sample: Bite mark swabs


If bite marks are present


Body fluids/DNA; other material


Note: In addition to documenting, photographing, and swabbing bite marks, an odonatologist may need to make casts, in order to match teeth to suspects. See Riviello (2013) for related guidelines.


Note: Use of an ALS may help guide identification of bite mark evidence, especially if fading.

Cotton-tipped swabs × 2 per site


Sterile water


· Moisten first swab with water and swab the areas inside and around the arches of the bite mark rather than from the tooth marks—this technique maximizes the yield of DNA containing material from sites where the lips and tongue of the biter would touch (Kaplan, 2011).

· Repeat with the second dry swab.

Sample: Head hair


If it is disclosed or suspected that the assailant has shed hair, or foreign materials from the assailant or crime scene may have been transferred to the patient’s head hair


In cases of delayed reports of suspected alcohol- or drug-facilitated sexual abuse or if chronic exposure to drugs is disclosed or suspected

Foreign material: hair, other; presence of drugs


Note: Many jurisdictions do not routinely collect plucked hair reference samples. Some will only collect these if the lab requests it at a later time.[13]


Note: In cases of delayed reports of suspected alcohol- or drug-facilitated sexual abuse or if chronic exposure to drugs is disclosed or suspected, collect head hair[14] at least 4 weeks after abuse. Hair analysis might help in identifying drug(s) used or chronic drug exposure.

Fine tooth comb, scissors


Collection paper


· Place paper under the patient’s head.

· Comb hair so that loose foreign material falls onto the paper.

· Remove the paper, place comb in center, and fold the paper to retain comb and specimen.

· For delayed reports/chronic exposure, collect at least 2 head hair samples (thickness of a pencil) by cutting them as close to the scalp as possible.[15]

· Follow jurisdictional/toxicology lab packaging/storage policies.

Contact staff at SAFEta.org with questions related to evidence collection and for suggestions regarding accommodations in specific situations with children with disabilities..

 Table of Contents B9. Sexual Abuse Facilitated by Alcohol and Drugs

[1] This chapter is adapted primarily from Day and Pierce-Weeks (2013).

[2] A minimum window of 72 hours since the abuse, noting that the window may widen with appropriate research. (See A5d. Timing of Evidence Collection)

[3] The Technical Working Group on Biological Evidence Preservation (2013) offers a resource at www.nist.gov/forensics/upload/NIST-IR-7928.pdf for those involved in biological evidence storage, tracking, preservation, and disposition.

[4] Use of dental floss is not recommended for additional forensic evidence collection in cases with oral penetration. Flossing can create increased opportunity for infection through micro-trauma to the gums.

[5] Although there is not current research to support extended hours for collection of oral evidence, research findings may be limited due to time frame guidelines for collection utilized by jurisdictions.

[6] Note that biological samples and DNA profiles from patients should be used only for investigation of the sexual abuse. Neither should be provided to law enforcement or prosecution for other cases in which patients may be suspected of juvenile delinquency, inadvertently given to health insurance carriers, or used for research purposes without consent. (One exception is that a forensic lab may input frequency information related to DNA profiles in its statistical database. In this case, victims’ identity should remain anonymous. Another variable to consider, however, is that each state/territory’s statutes determine who can have access to records of child abuse and neglect reports maintained by state child protective service or social service agencies—some may allow researchers to access some information in these records (See Child Welfare Information Gateway, 2013b.) In addition to secure storage and disposal of forensic samples as discussed in A5e. Evidence Integrity, criminal justice agency policies should be in place and followed for appropriate disposal of children’s DNA profiles.

[7] Most jurisdictions and crime labs accept buccal swabs. If they do not, however, consider dried blood sample cards, unless drawn blood is needed for medical or toxicological reasons.

[8] Labs doing toxicology testing request the maximum amount of blood volume allowable by weight of child (see the chart at www.ucdmc.ucdavis.edu/clinicaltrials/StudyTools/Documents/Blood_Draws_Maximum_Allowable.doc by the UC Davis Medical Center). As noted, it is similar to ones used by: Committee on Clinical Investigations, Children’s Hospital, Los Angeles, California; Baylor College of Medicine, Dallas, Texas; and Cincinnati Children’s Hospital Institutional Review Board, Ohio (Adapted by: R. Jack, Children’s Hospital and Regional Medical Center Laboratory, Seattle, Washington, 2001). If the child has coexisting medical conditions, it might lead to taking less than the maximum amount of blood volume by weight.

[9] For patients with mobility impairments, put the collection sheet on the exam table and leave it in place until the examination is completed. If patients prefer to disrobe in their wheelchairs, sheets can be tucked around the wheelchair to catch debris. Avoid putting chairs on paper, as debris from wheels may contaminate forensic evidence (Massachusetts Department of Health, 2005).

[10] If the patient has vomited, treat it as a supplemental specimen. Vomit samples are mainly used as a toxicological specimen in drug-or alcohol-facilitated cases. Collect as much of the sample as possible by using a spoon, eyedropper-type suction device, or other tool that is consistent with biohazard procedures. Place in appropriate container that has a lid with a tight seal. Follow jurisdictional policy for refrigerated storage. If any vomitus is on clothing, sheets, or other objects, also put the items in an appropriate container to prevent leakage and contamination (Ohio Chapter of the AAP Committee on Child Abuse and Neglect, 2009).

[11] Although there is not current research to support extended hours for collection of such evidence on the child’s skin, research findings may be limited due to time frame guidelines for collection utilized by jurisdictions.

[12] For example, if there was penetration of the labia into the vestibule, it would be appropriate to wet-dry swab the outer surface of the labia majora, and then to dry swab the inner aspect of the labia majora in the vestibule that is already moist, as well as the fossa (without contacting the hymen).

[13] Whatever the jurisdictional policy, patients should be informed about the purpose of collection, procedures used to collect samples, discomfort that may be involved, and how these samples may be used during the investigation and prosecution. If hair reference samples are not collected at the initial examination, examiners should inform patients that a need might exist to collect these samples for crime lab analysis at a later date. They should be aware that hair evidence collected at a later date may not be as conclusive as if it were collected at the time of the initial examination (e.g., due to the fact that hair characteristics can change over time). When these samples are collected, the indications, timing, and techniques vary. Jurisdictional policies should be in place and followed.

[14] Head hair is the preferred sample, but pubic, axillary, torso, or leg hair may also be collected for analysis (UN Office on Drugs and Crime, 2011). However, prepubescent children typically have limited to no hair in these areas. Analysis in such instances could also be limited because as the growth rate of non-head hair is not well established as is with head hair (UN Office on Drugs and Crime, 2011). 

[15] Sufficient hair collection is needed to be able to carry out routine tests and allow for a repeat analysis or confirmation test by a second laboratory—if necessary, hair samples can be collected from one or multiple site on the head (Cooper, Kronstrand, & Kintz, 2012). See the Society of Hair Testing at www.soht.org/index.php/statements/9-nicht-kategorisiert/85-statement-2011 for more detailed collection instructions.