Multidisciplinary forensic or crime laboratories usually divide by physical evidence kind. Some regions share instrumentation, while others need specialized equipment, instrumentation, and training. Criminalists may move between lab areas depending on their training, experience, and skill. The facility's size and workload may combine or split some sections.

Identification of drugs and toxicology

Using forensic chemistry and modern instrumental techniques, the laboratory's toxicology and drug identification department isolates, identifies, and quantifies alcohol, drugs, poisons, and other harmful substances. To determine the severity of a criminal drug charge, bulk volumes of marijuana, heroin, LSD, or cocaine must be weighed, analyzed, and quantified. Analyzing other liquid, solid, or gaseous components can reveal toxic substances. Many crime laboratories check blood for alcohol and drug levels in situations of driving while impaired or inebriated, as well as body tissues and fluids for death investigation. Drugs found may be legal or prohibited. Carbon monoxide, cyanide, insecticides, and heavy metals are common toxins. Quantitative blood and tissue levels of these chemicals and their metabolites may indicate therapeutic, hazardous, or lethal concentrations in the body and help determine the substance's role in mortality. In seizure disorder victims, the absence of anticonvulsive medications may explain their behavior or death.

Arson Analysis

The distillation of steam

The charred material is heated and distilled with steam before being condensed with cold water. Volatile hydrocarbons are liquidated before examination.

Extraction of solvents

A recognized solvent such carbon disulfide, methylene chloride, or hexane is mixed with the burned sample and shaken to dissolve petroleum distillates and other volatiles. Evaporating this extract reduces its volume for analysis.

Cold head space

The top of the sample container is punctured and a stopper is added so that a head space vapor sample can be removed and examined with a syringe.

Heated head space

After putting the cork on the sample container, the oven heats it to 100°C or less. Heat concentrates head space vapors from the burned matrix. The cool head space technique is less sensitive and popular.

Charcoal vapor concentration

A nitrogen or air-based inert gas purge of the heated sample container concentrates volatiles in a charcoal-filled tube. Heat or a small amount of carbon disulfide desorbed the charcoal for analysis.

Serology

Forensic serology studies, identifies, and classifies body fluids, tissues, secretions, and excretions. Perspiration, urine, gastric contents, and feces can be tested for characterization, but blood, sperm, and saliva are most common. The laboratory receives dried stains on clothing or other items from the scene, victim, or suspect. The investigations must include control samples of clean surfaces from which the suspicious stains were taken. Standard victim/suspect blood samples are also utilized for comparison.

Trace Evidence

The forensic scientist or criminalist who analyzes and compares trace evidence must be familiar with many substances that may be submitted to the crime lab in trace amounts.

Firearms and Toolmarks

The crime lab's firearms and toolmark section examines weapons, ammunition, and surface scrapes and imprints from prying and cutting instruments.

Fingerprint Recognition

This section of a laboratory is often referred to as the latent print section.

Forensic Photography

Forensic photography is a vital component of crime scene investigation because it provides for the documentation of the victim's position and the surrounding environment prior to the forensic pathologist's examination and the removal of the body to the mortuary.