A buccal swab, or cheek swab, is the preferred method of obtaining a sample for two types of profile tests commonly performed in medicine and, sometimes, in law enforcement investigations. The swab itself is much like a cotton-tipped applicator used in the application of makeup, but it is different in a couple of key areas. First, the swab has a cotton tip only at one end. Second, the shaft of the swab is generally longer than those used for personal applications.
The two tests for which buccal swabs are most often used are deoxyribonucleic acid (DNA) tests, and human leukocyte antigen (HLA) tests. DNA tests typically seek to identify or match a person based on a sample obtained from somewhere else. This could help determine paternity for a child, identify a deceased victim, or help put a suspect at a particular crime scene in which a sample was left behind. By contrast, the medical community generally uses HLA tests in order to identify who might be a good donor for an organ or bone marrow transplant.
The procedure for a buccal swab is relatively simple. A person removes the swab from a sterile package and rubs the cotton tip against the inside of another person's cheek. The name buccal actually means mouth cavity or cheeks. This removes cells that can then be tested without any discomfort to the person being swabbed. The swab is then placed in another sterile container, generally a hard plastic tube, and sent to a laboratory for examination.
Getting a buccal swab typically involves going to a medical lab or a doctor. Police investigators may have an officer obtain the sample from a suspect on the spot. Typically, this can only be done with a suspect's permission. In cases where permission is not granted, the officer or investigator could go to the court and request that a judge require the suspect to cooperate with the test by means of a warrant.
The accuracy of a buccal swab is very though not perfect. In fact, a blood test and a buccal swab test provide the same level of accuracy, which is why the swabs have become so popular in recent years. It may be somewhat easier to accidentally contaminate a swab, however, if it were to come into contact with another person's bodily fluids, such as blood, sweat, or semen, but this is rare if proper precautions are applied.
Due to the relatively simple procedure and inexpensive costs of a buccal swab, it is also the preferred method for home DNA tests. Individuals seeking to confirm paternity or get a DNA ancestry profile can order home kits. The individual can them swab himself, or have another person do it, and send the test back to a lab for analysis. Such tests may not be considered proof in a court of law because no chain of custody rules are followed, but it could provide information to an individual seeking to move forward with a civil suit regarding family law.