What Is a Forensic Exam and What Happens During One?

A forensic exam is a specialized medical evaluation that documents injuries, collects biological evidence, and provides treatment in cases involving violence or sexual assault. The most widely known version is the sexual assault medical forensic exam (sometimes called a SAMFE or “rape kit exam”), in which a trained professional gathers physical evidence from a patient’s body and clothing while also treating injuries, screening for infections, and offering emergency contraception. Forensic exams serve a dual purpose: they address immediate health needs and preserve evidence that could later support a legal case, though a patient can usually have one without committing to a police report.

Who Performs the Exam and Where It Happens

Most sexual assault forensic exams are performed by a sexual assault nurse examiner (SANE) or a broader category known as a forensic nurse examiner (FNE). These are registered nurses with additional training in evidence collection, injury documentation, and trauma-informed patient interaction. The specialty emerged in the United States starting in the 1970s, when nurses working in emergency departments pushed to create a distinct discipline that could administer the medical forensic exam independently of physicians.¹ Today, forensic exams happen in emergency departments, dedicated sexual assault response centers, and sometimes child advocacy centers, depending on the patient’s age and local resources.

A forensic nurse examiner’s scope is broad. They assess and treat injuries, provide accurate documentation, screen for sexually transmitted infections and offer prophylaxis, perform HIV risk assessments, supply emergency contraception, provide emotional support, collect forensic evidence for possible legal proceedings, and connect patients with referrals and community resources.² That combination of medical treatment and evidence handling is what sets a forensic exam apart from a standard trip to the emergency room.

How Consent Works Throughout the Exam

One of the most important things to understand is that a forensic exam is not an all-or-nothing process. Consent is requested at every stage. The examiner should ask permission before each step, pause for questions, and remind the patient that they can decline any part of the exam at any time, even if they initially agreed.² You can say yes to the medical treatment and no to evidence collection, or agree to swabs but decline a pelvic exam. Nothing is forced.

This approach reflects a broader shift in forensic practice toward trauma-informed and victim-centered care. Recent research has emphasized minimizing harm through these approaches during sexual assault examinations.³ In practice, that means the examiner explains what they are doing and why before they do it, uses language that gives you control over the pace, and does not pressure you toward any particular decision about reporting.

What Happens Step by Step

While the exact sequence varies by jurisdiction and program, a sexual assault forensic exam generally follows a recognizable pattern. Understanding the steps beforehand can reduce anxiety about the process.

History and Narrative

The exam typically begins with a detailed but sensitive conversation. The examiner asks about what happened, not to judge or investigate, but to guide where they look for injuries and what evidence to prioritize. If you were assaulted in a specific way, that information tells the nurse which body areas to examine and what swabs to collect. The examiner also asks about your medical history, medications, and any recent consensual sexual activity, because this information helps forensic labs interpret the biological evidence later.

Head-to-Toe Physical Examination

The examiner performs a full-body check for injuries, including cuts, bruises, redness, swelling, and bite marks. They photograph injuries using standard clinical photography and, increasingly, specialized lighting. Many programs now use alternate light sources (ALS), which emit specific wavelengths that can reveal bruises the naked eye might miss, particularly on darker skin tones. Research has found that wavelengths around 415 nanometers viewed through a yellow filter detect bruises more reliably than standard white light across all skin pigmentation categories.⁴ These two specific ALS wavelengths (415 nm and 450 nm) were the only combinations that outperformed white light on patients with brown or dark skin, a finding with real implications for reducing health and criminal justice disparities.

A systematic review of the evidence on alternate light sources confirmed that narrowband wavelengths within the visible spectrum outperform conventional white light for bruise detection and documentation, though the technology still has limitations. Factors like tattoos, moles, cosmetic products, and scar tissue can complicate the readings, and more research is needed on how well ALS distinguishes real bruises from these false positives.⁵

Genital and Anal Examination

If the assault involved genital or anal contact, the examiner conducts a more focused examination of those areas. This is often the part patients are most anxious about, and examiners typically spend extra time explaining what they will do and checking in. The exam requires a careful, methodical approach to identify injuries and collect biological material, with an understanding of anatomy and physiology that helps interpret what the findings mean.⁶ Magnification tools such as a colposcope, which is essentially a lighted magnifying instrument, are sometimes used to document subtle injuries.

Evidence Collection

This is the “rape kit” portion of the exam. The examiner collects biological evidence using swabs from the mouth, genitals, anus, and skin depending on what happened. Clothing may be collected as well. Each item is carefully handled to avoid contamination, degradation, or loss of evidence, and specific procedures govern selection, collection, packing, sealing, labeling, storage, preservation, and transport of every sample.⁷

The type of swab and collection technique matter. Research comparing different collection methods found that techniques in which the entire swab surface contacts the evidence, such as the “double swab technique,” yield significantly better results. Nylon-tipped swabs also perform better than cotton ones because they release the collected sample more effectively during laboratory processing, producing higher amounts of recoverable DNA.⁸

Why Timing Matters

One of the most common questions people have is how long after an assault they can still have a forensic exam. The short answer is that sooner is better, but later is not useless. A large study of over 1,000 sexual assault cases found that the likelihood of recovering DNA from vaginal swabs remained meaningful for up to three days after the assault, dropping from about 35% on the first day to roughly 23% on the third day. Skin swabs collected within the first day yielded DNA about 41% of the time, while anal and rectal swabs produced results about 22% of the time in the same window. Oral samples were the least productive, with fewer than 10% yielding DNA evidence, and all successful oral recoveries occurred within 24 hours.⁹

These numbers do not mean that going in after 72 hours is pointless. Many programs will perform an exam up to five or even seven days after an assault, and some types of evidence, like injury documentation, remain relevant regardless of how much time has passed. But from a purely DNA standpoint, every hour counts, particularly for oral evidence. If you are unsure whether to go, the general guidance is to go as soon as you feel able to.

Medical Treatment During the Exam

A forensic exam is not just about evidence. It is also a medical visit, and the examiner addresses immediate health concerns. Typical medical care offered during or after the exam includes:

STI prophylaxis: Medications to prevent bacterial infections like gonorrhea and chlamydia.
HIV PEP: Post-exposure prophylaxis for HIV, ideally started within 72 hours of exposure.
Emergency contraception: To prevent pregnancy from the assault.
Pregnancy testing: To establish a baseline.
Wound care: Treatment for any physical injuries sustained during the assault.

Survey data on forensic nursing programs shows that the offering of HIV PEP, pregnancy information, pregnancy testing, and emergency contraception has been increasing over time as programs expand their scope of comprehensive care.¹⁰

Toxicology Screening When Drugging Is Suspected

If there is any suspicion that drugs were used to facilitate the assault, toxicology testing becomes part of the forensic exam. This typically involves collecting blood and urine samples. The challenge is that many substances used in drug-facilitated assaults metabolize quickly, making detection a race against the clock. Research from Eastern Denmark covering suspected drug-facilitated sexual assault cases found that the time between assault and sample collection tended to be longer for suspected drugging cases (12 to 24 hours) compared to other sexual assaults (under 12 hours), which complicates detection.¹¹

That same research found positive toxicology results in 86% of suspected drug-facilitated cases. The most commonly detected substances were alcohol (45%), recreational drugs of abuse (38%), antidepressants (14%), antihistamines (12%), and benzodiazepines (11%). The stereotype of a stranger slipping a hypnotic drug into a drink was relatively uncommon; hypnotics were detected in only 7% of cases. The data suggested that most drug-facilitated assaults were opportunistic, taking advantage of someone already impaired by alcohol or other substances, rather than proactive drugging by the perpetrator.¹¹

Strangulation Assessment

Sexual assaults frequently co-occur with other forms of violence, and non-fatal strangulation is one of the most dangerous. A forensic exam is particularly valuable here because strangulation often leaves minimal visible evidence. One study of 580 sexual assault-related strangulation cases found that about 19% of victims had no injuries visible on physical exam at all, even though nearly 30% reported losing consciousness during the attack. The most common injury location was the neck (57%), followed by the mouth (29%).¹²

Another study of domestic violence-related strangulation found that 52% of cases involved multiple strangulation attacks during the same incident, and 60% of victims had a history of strangulation within the relationship. That study argued that a forensic exam is essential to identify serious symptoms and injuries that might not be immediately obvious, and to collect evidence for legal proceedings.¹³

Timing matters here too, especially for detecting petechiae, the tiny pinpoint hemorrhages that are a hallmark sign of strangulation. Research analyzing over 500 strangulation cases found petechiae in about 10% of cases overall, and they were significantly more likely to be detected when the exam occurred sooner after the event (an average of 26 hours versus 61 hours for cases without petechiae). Petechiae in the conjunctiva of the eyes tend to appear and fade early, while those behind the ears can persist longer.¹⁴

The Chain of Custody

Everything collected during a forensic exam feeds into a legal chain of custody, the documented trail that tracks who handled the evidence, when, and how. If the chain is broken or improperly documented, the evidence can be challenged or excluded in court. Proper collection and disposition of evidence is critical so that a perpetrator does not go free because forensic evidence was mishandled, yet protocols for maintaining the chain of custody are not always clearly established at every facility.¹⁵ In practice, this means every swab, clothing item, and photograph is labeled, sealed, and signed off at each transfer point from the exam room to the lab to the courtroom.

You Do Not Have to File a Police Report

A widespread misconception is that getting a forensic exam means you have committed to pressing charges. In the United States, nearly every state offers a formalized option to have a sexual assault kit collected without filing a police report. A recent study documenting each state’s policies found that all but one state has some version of this “non-report” option, with six states offering multiple pathways. Storage timelines for unreported kits range widely, from 90 days to 75 years, with an average of about 17 years.¹⁶

The same study found that 20 states offer a free medical exam even without forensic evidence collection, and 22 states extend victim compensation fund eligibility to individuals who have a non-report kit collected. Eleven states grant minors access to non-report options in at least some circumstances.¹⁶ The idea is to preserve evidence now in case you decide to report later, without forcing that decision in the immediate aftermath of an assault.

Exams for Children and Adolescents

Forensic exams for children require specialized expertise. A medical examination is indicated whenever sexual abuse is suspected and should ideally be performed within seven days to secure trace evidence. Examining prepubertal children calls for specific positioning, such as the frog-leg or knee-chest position, along with adequate illumination and magnification using tools like a colposcope. This level of care is necessary to distinguish normal anatomical variants from subtle signs of trauma, something that takes significant training.¹⁷ Pediatric exams are typically performed in child advocacy centers where the environment is designed to be less clinical and more child-friendly.

Exams for Male Patients

Men and boys can also receive forensic exams after sexual assault, though they seek them far less frequently. The exam process is largely the same: a trained medical professional obtains a narrative of the assault, collects physical evidence such as saliva and bodily fluids based on that report, and provides post-exposure prophylactic treatments for STIs, emergency contraception when relevant, and treatment of assault-related injuries.¹⁸ Barriers for male patients tend to be psychological and social rather than procedural. Many men do not know forensic exams are available to them, and stigma around male sexual victimization makes seeking care less likely.

Emerging Technologies in Forensic Exams

The basic structure of the forensic exam has remained fairly stable for decades, but several technologies are beginning to change how evidence is documented and processed. One innovation is three-dimensional body scanning. Some forensic institutes now use multi-camera devices containing 70 cameras positioned at different heights around a central platform. All cameras fire within a fraction of a second, producing a complete 3D model of the patient’s body that can be rotated and examined later in court, providing a more comprehensive record than traditional two-dimensional photographs.¹⁹

On the laboratory side, forensic evidence backlogs have long been a problem. Thousands of sexual assault kits have gone untested for years in some jurisdictions. AI-enhanced DNA interpretation software and robotic liquid handling systems are being explored as ways to streamline the analysis pipeline, increase accuracy, and clear those backlogs faster.²⁰ Whether these tools deliver on their promise at scale is still being evaluated, but the direction is toward faster, more accurate processing of the evidence that forensic exams produce.

Barriers to Follow-Up Care

The forensic exam itself lasts a few hours, but the aftermath stretches much longer. Mental health follow-up is a well-recognized need, yet accessing that care proves difficult for many survivors. Research on barriers to mental health care after a forensic exam found a complicated pattern: people with more severe PTSD symptoms reported more obstacles to accessing treatment, yet they were also more likely to say they intended to seek care when free services were offered. The groups least likely to seek follow-up care were students and those with problematic drinking patterns, both of whom showed lower rates of pursuing any post-exam services including mental health support and advocacy.²¹

Forensic nursing programs increasingly try to build follow-up into the exam process itself, providing referral lists, scheduling check-in calls, and connecting patients directly with advocacy organizations before they leave the exam room. The evidence suggests that the moment of the exam is one of the few points of contact where a system can reach survivors who might otherwise fall through the cracks.

1
PubMed. Legal mobilization in medicine: Nurses, rape kits, and the emergence of forensic nursing in the United States since the 1970s
2
PubMed Central. Trauma- and Violence-Informed Empowering Care for Sexual Assault Survivors
3
Feminist Legal Studies. Medico-Legal Evidence: Survivor Relational Autonomy and Informed Consent in Sexual Assault Examinations
4
PubMed. Predicting alternate light absorption in areas of trauma based on degree of skin pigmentation: Not all wavelengths are equal
5
PubMed Central. Examining the use of alternative light sources in medico-legal assessments of blunt-force trauma: a systematic review
6
PubMed Central. Sexual Assault: Forensic Examination in the Living and Deceased
7
PubMed Central. Biological Evidence Management for DNA Analysis in Cases of Sexual Assault
8
PubMed. Contribution to the Development of Guidelines in the Analysis of Biological Evidence in Sexual Assault Investigations
9
Forensic Science International: Genetics Supplement Series. Biological and DNA evidence in 1000 sexual assault cases
10
PubMed. Comprehensive Care of Patients Following Sexual Assault: A Cross-Sectional Survey of Services Provided by Forensic Nursing Programs
11
PubMed. Uncovering forensic evidence of drug-facilitated sexual assault: Toxicological findings from Eastern Denmark from 2015-2022
12
PubMed Central. Symptoms and Physical Exam Findings in Sexual Assault-related Non-fatal Strangulation
13
PubMed. Forensic documentation of non-fatal strangulation
14
PubMed. Petechiae in non-fatal strangulation: Prevalence, predictors and time-dependent detectability in forensic assessment
15
AORN Journal. Maintaining the Chain of Custody Evidence Handling in Forensic Cases
16
Sexuality Research and Social Policy. Alternative Reporting Options Across the United States: Documenting Each State’s Options for Sexual Assault Kit Collection Without a Police Report
17
PubMed Central. Physical Examination in Child Sexual Abuse: Approaches and Current Evidence
18
PubMed Central. Characteristics of Sexual Assault Among Men Receiving a Forensic Medical Examination
19
PubMed. Forensic examination of living persons in 3D models
20
Advance Social Science Archive Journal. New Technologies in Sexual Assault Evidence Processing: The Future with Automation and AI
21
PubMed Central. Barriers to Accessing Mental Health Care after A Sexual Assault Medical Forensic Exam