A medical examiner determines cause of death by working through a sequence of steps: reviewing the scene and the person’s medical history, performing an external examination of the body, often running imaging, conducting an internal autopsy when the case calls for it, and sending samples to the laboratory for toxicology and tissue analysis. The findings from each step are weighed together, and the specific disease or injury that started the chain of events leading to death is named as the cause. Most of the work is methodical rather than dramatic, and the full answer can take anywhere from a few days to several months.
Which Deaths Reach a Medical Examiner
Most deaths in the United States are never investigated. When someone dies of a known illness while under a doctor’s care, the attending physician signs the death certificate and the case ends there. The national autopsy rate has sat below 10% for years.1Centers for Disease Control and Prevention. Products – Data Briefs – Number 67
Deaths that do land on a medical examiner’s desk share certain features. Rules vary by jurisdiction, but the categories are broadly consistent: deaths from violence, including accidents, suicides, and homicides; sudden or unexpected deaths in someone not under a doctor’s care; deaths under suspicious or unusual circumstances; unattended deaths; and deaths in custody.2Centers for Disease Control and Prevention. Medical Examiners’ and Coroners’ Handbook on Death Registration Infant and child deaths where abuse or neglect is suspected generally fall under the medical examiner’s authority as well. The common thread is that something about the death requires independent medical investigation before anyone can confidently say what happened.
The Scene and the Medical History
The investigation starts before anyone touches the body. A medical examiner or a trained investigator reviews the police report, witness statements, and the circumstances at the scene. Where was the body found, and in what position? Were there medications nearby, signs of a struggle, or evidence of drug use? Those details shape every decision that follows, including whether a full autopsy is warranted at all.
Medical records are pulled whenever they can be. A history of heart disease, cancer, psychiatric treatment, or substance use can change how the examiner reads the physical findings. A 60-year-old with severe coronary artery disease who collapses at home tells a different story from an otherwise healthy 30-year-old found in the same position. Scene context and medical history are not just preliminary background. They travel with the examiner through every later stage.
The External Examination
Once the body reaches the facility, the external examination is far more thorough than a visual once-over. The examiner documents wounds, bruises, abrasions, scars, tattoos, needle marks, and any signs of prior medical intervention such as IV lines or surgical incisions. Clothing is examined and catalogued, especially where trauma is involved.
Three postmortem changes get particular attention. Rigor mortis, the stiffening of muscles after death, gives clues about how long ago the person died. Livor mortis, the gravity-driven pooling of blood that discolors the skin’s lowest points, can reveal whether the body was moved. Algor mortis, the cooling of the body, provides another rough estimate of time of death. None of these are precise on their own, but together they build a timeline. Trace evidence such as fibers, hair, and material under the fingernails is also collected, particularly when foul play is suspected.
Imaging Before the First Incision
Many offices now scan every body with a CT scanner before making any cut. Postmortem CT can detect fractures, projectiles, internal bleeding, gas patterns, and foreign objects that might be missed or that help guide the autopsy itself.3National Institute of Justice. Postmortem CT Scans Supplement and Replace Full Autopsies
CT is especially useful for injuries to the hands, feet, and face, areas that are not routinely dissected. In one case, a scan revealed a broken foot on a woman found near a border wall, a contributing cause of death that a standard autopsy would have missed. In some drug-related deaths, offices combine CT with rapid toxicology and medical history to reach a cause of death without a full autopsy. At least one major office reported its full autopsy rate dropped from roughly 85% to around 50% after adopting universal CT scanning.3National Institute of Justice. Postmortem CT Scans Supplement and Replace Full Autopsies X-rays are also used routinely, particularly to locate bullets or bone fractures.
The Internal Autopsy
When a full autopsy is warranted, the internal examination is the centerpiece. It typically opens with a Y-shaped incision running from each shoulder to the breastbone and then down to the pubic bone, giving the pathologist access to the chest and abdominal cavities.4HowStuffWorks. How Autopsies Work The physical procedure itself takes roughly two to four hours.
Each organ is removed, inspected, and weighed. The heart is checked for coronary artery disease, valve abnormalities, or enlargement. The lungs are examined for fluid, infection, or blood clots. The liver, kidneys, and other abdominal organs are assessed for disease or injury. Major blood vessels are opened and examined. Tissue samples are taken from each organ for later microscopic analysis.4HowStuffWorks. How Autopsies Work Throughout, the pathologist is looking for anything that explains why this person died: a ruptured aortic aneurysm, a tumor, a stab wound track, signs of asphyxiation.
The Brain
The brain is handled differently. In most cases it cannot be properly examined during the autopsy itself, because unfixed brain tissue is too soft to section cleanly. It is removed and placed in formalin preservative for two to three weeks before a neuropathologist cuts and examines it. Certain hemorrhages, subtle disease, and evidence of traumatic brain injury only become visible after fixation. This is one reason a final report can take months even when the rest of the examination is straightforward.
Laboratory Testing
The autopsy usually raises questions that only the laboratory can answer. Much of the waiting happens here, and cases that seem obvious on the table sometimes turn on what comes back from the lab.
Toxicology
Toxicology screens blood, urine, vitreous humor (the fluid inside the eye), and sometimes organ tissue for drugs, alcohol, and poisons.5National Institute of Justice. New Screening Method to Detect Drugs and Poisons Postmortem Analysis does not just show whether a substance is present. It measures concentration, which is what distinguishes a therapeutic dose from a lethal one. Results typically take four to ten weeks and sometimes longer, largely because forensic toxicology labs are chronically backlogged. This is the single biggest reason autopsy reports get delayed, and it is why families often hear “cause of death pending toxicology” for weeks after the funeral.
Histology
Histology is microscopic examination of the tissue samples collected during the autopsy. Thin slices are mounted on glass slides, stained, and read under a microscope. That can reveal conditions invisible to the naked eye: inflammation of the heart muscle, microscopic clots in the lungs, early-stage cancers, or tissue damage from electrical injuries. Histology usually comes back within three to eight weeks.
Microbiology and Specialist Consultations
When infection is suspected, microbiology cultures can identify bacteria, viruses, or fungi that may have contributed to the death. In cases involving decomposed or skeletal remains, forensic anthropologists analyze bone to estimate age, sex, stature, and evidence of trauma.6American Dental Association. Forensic Dentistry and Anthropology Forensic odontologists use dental records for identification, since teeth resist decomposition far longer than soft tissue.7PubMed Central. Dental Evidence in Forensic Identification – An Overview, Methodology and Present Status Each outside consultation adds time, since samples have to be shipped and specialists need their own review period.
Cause, Mechanism, and Manner Are Not the Same Thing
These three terms sound interchangeable, and confusing them is one of the most common misunderstandings families run into when they read the report.
The cause of death is the specific disease or injury that started the chain of events leading to death. A gunshot wound to the chest, metastatic lung cancer, or blunt force head trauma are all causes. The mechanism of death is the physiological response that actually killed the person: hemorrhage, sepsis, cardiac arrest. Mechanism is not listed as the cause because it is not specific enough. Cardiac arrest, for example, is the mechanism of virtually every death. The manner of death is the examiner’s classification of the circumstances.
The five recognized manners are:
- Natural: death from disease or an internal condition, with no external cause involved.
- Accident: death from an unintentional injury or poisoning.
- Suicide: death that was self-inflicted with the intent to die.
- Homicide: death caused by the actions of another person. This is a medical classification, not a legal one, and a homicide ruling on a death certificate does not mean anyone has been charged with a crime.
- Undetermined: the evidence does not clearly point to one manner over another.
The manner determination is a judgment that weighs everything: scene findings, medical history, autopsy results, and lab work. The manner listed on a death certificate has no direct legal bearing on criminal prosecution or insurance claims. Those are separate processes with their own standards of proof.
When the Answer Is “Undetermined” or “Pending”
An undetermined manner of death is not a failure. It means the examiner reviewed the evidence and concluded that it genuinely does not favor one classification over another. This happens more often than people expect, particularly in drug-related deaths where the line between accident and suicide can be impossible to draw, and in cases where decomposition has destroyed critical evidence.
Pending means the investigation is not finished, usually because toxicology or other lab results have not come back. Once results arrive, the examiner updates the manner on the death certificate. Some offices also review old undetermined cases periodically to see whether new information would allow a reclassification, and a death certificate can be amended if the examiner later reaches a definitive conclusion.
The Death Certificate and the Autopsy Report
The findings ultimately land in two documents. On the death certificate, cause of death is recorded as a chain of events, with the immediate cause on the first line and underlying causes listed beneath it, along with any contributing conditions and the manner of death.2Centers for Disease Control and Prevention. Medical Examiners’ and Coroners’ Handbook on Death Registration Only a licensed physician, medical examiner, or in some jurisdictions a coroner may sign as certifier of cause of death.
The full autopsy report is a far more detailed document that includes the complete external and internal findings, organ weights, microscopic analysis, toxicology results, and the pathologist’s interpretation. Preliminary findings from the physical exam are often available within 24 to 72 hours, but the final written report typically takes six to twelve weeks, and complex cases stretch longer. Families can usually request a copy of the final report from the medical examiner’s office, though policies and fees vary by jurisdiction.