A throat culture is a laboratory

diagnostic test A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic ...

that evaluates for the presence of a bacterial or fungal infection in the throat. A

sample Sample or samples may refer to: Base meaning * Sample (statistics), a subset of a population – complete data set * Sample (signal), a digital discrete sample of a continuous analog signal * Sample (material), a specimen or small quantity of s ...

from the throat is collected by swabbing the throat and placing the sample into a special cup (

culture Culture () is an umbrella term which encompasses the social behavior, institutions, and norms found in human societies, as well as the knowledge, beliefs, arts, laws, customs, capabilities, and habits of the individuals in these groups.Tyl ...

) that allows infections to grow. If an organism grows, the culture is positive and the presence of an infection is confirmed. The type of infection is found using a

microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...

, chemical tests, or both. If no infection grows, the culture is negative. Common infectious organisms tested for by a throat culture include

Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is us ...

known for causing thrush and

Group A streptococcus Lancefield grouping is a system of classification that classifies catalase-negative Gram-positive cocci based on the carbohydrate composition of bacterial antigens found on their cell walls. The system, created by Rebecca Lancefield, was historic ...

known for causing

strep throat Streptococcal pharyngitis, also known as streptococcal sore throat (strep throat), is pharyngitis (an infection of the pharynx, the back of the throat) caused by ''Streptococcus pyogenes'' a gram-positive, group A streptococcus. Common symptom ...

scarlet fever Scarlet fever, also known as Scarlatina, is an infectious disease caused by ''Streptococcus pyogenes'' a Group A streptococcus (GAS). The infection is a type of Group A streptococcal infection (Group A strep). It most commonly affects childr ...

, and

rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a streptococcal throat infection. Signs and symptoms include fever, multiple painful jo ...

. Throat cultures are more sensitive (81% sensitive) than the

rapid strep test The rapid strep test (RST) is a rapid antigen detection test (RADT) that is widely used in clinics to assist in the diagnosis of bacterial pharyngitis caused by group A streptococci (GAS), sometimes termed strep throat. There are currently seve ...

(70%) for diagnosing strep throat, but are nearly equal in terms of specificity.

Purpose

A throat culture may be done to investigate the cause of a

sore throat Sore throat, also known as throat pain, is pain or irritation of the throat. Usually, causes of sore throat include * viral infections * group A streptococcal infection (GAS) bacterial infection * pharyngitis (inflammation of the throat) * tonsi ...

. Most sore throats are caused by viral infections. However, in some cases the cause of a sore throat may be unclear and a throat culture can be used to determine if the infection is bacterial. Identifying the responsible organism can guide treatment.

Technique

The person receiving the throat culture is asked to tilt his or her head back and open his or her mouth. The health professional will press the tongue down with a

tongue depressor A tongue depressor (sometimes called spatula) is a tool used in medical practice to depress the tongue to allow for examination of the mouth and throat. The most common modern tongue depressors are flat, thin, wooden blades, smoothed and rounded ...

and examine the mouth and throat. A clean swab will be rubbed over the back of the throat, around the

tonsils The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play a ...

, and over any red areas or sores to collect a sample. The sample may also be collected using a throat washout. For this test, the patient will gargle a small amount of salt water and then spit the fluid into a clean cup. This method gives a larger sample than a throat swab and may make the culture more reliable. A culture for

Streptococcus pyogenes ''Streptococcus pyogenes'' is a species of Gram-positive, aerotolerant bacteria in the genus ''Streptococcus''. These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains. They are ...

can take 18–24 hours when grown at 37 degrees Celsius (body temperature).

References

{{Clinical microbiology techniques Medical tests Microbiology techniques

Purpose

Technique

See also

References