Unlike giving a blood sample, there is little preparation required for a throat culture. The nurse will ask the patient to open his or her mouth and then wipe the back of the throat with a cotton swab to obtain some cell samples.



After the throat sample has been collected, the swab is put into a container and labelled. In many places, the label will be pre-printed with the patient's name and identification number.


After the sample has been labelled, it is transported to the laboratory to be logged into the laboratory's computer system. The tube label contains all the information necessary to ensure that the sample is analysed for all the tests requested and the results are matched to your name.


Once in the lab, a biomedical scientist will transfer the throat cells that are on the swab to a material (agar) in a petri dish that will encourage the growth of bacteria. To do this, the swab is gently rubbed or streaked over the surface of the agar.


The sealed, labelled petri dish is placed in an incubator, which is a chamber that maintains a constant temperature that is optimal for the growth of the bacteria. The culture usually remains in the incubator for 24 - 36 hours to allow sufficient time for any bacteria that may be present to grow.


After the incubation, a scientist will visually examine the culture. Some bacteria have a characteristic appearance that enables the scientist to identify the specific bacteria. In some situations, additional tests may be needed to make the identification. Not all bacteria are harmful and require treatment.

Testing for treatment

If harmful bacteria have been identified in the throat culture, the laboratory will do an additional test using different types of antibiotics to see which one is most likely to stop the infection. This test starts by coating the surface of another agar dish with the bacteria. Antibiotics that have been absorbed into white paper discs are placed on the plate. If an antibiotic stops the bacteria on the plate from growing, it appears as a clear halo around the disc. This tells the doctor which antibiotic they can prescribe to cure the throat infection.

Getting results

The culture results will be recorded in the laboratory’s computer system. The results may be sent to the doctor’s computer, faxed, delivered by courier or posted to the doctor's surgery.