Throat swab culture sensitivity

Throat swab cultured on a blood agar plate has a sensitivity rate of 90-95% in detecting the presence of S pyogenes in the pharynx. This sensitivity depends on properly obtaining the specimen.

- Sample type (Agar):

When strep is suspected, the throat material is cultured on blood agar that has been prepared as a broth and poured into petri dishes (plates) where it solidifies into a gel.

- Uses:

A throat swab culture is a laboratory test that is done to identify germs that may cause infection in the throat. It is most often used to diagnose strep throat.

- Precautions:

Have the patient open the mouth and relax the tongue Press the tongue down using a tongue depressor. Gently rub the swab against both tonsils and the posterior pharynx. Place the swab in the culture medium, transport medium, or sterile test tube.

- Interfering Factors:

A throat culture is more accurate than the rapid strep test. The rapid strep test can give false-negative results even when strep bacteria are present. When the results of a rapid strep test are negative, many doctors recommend doing a throat culture to make sure that strep throat is not present.

- Pre analytical errors:

Patient preparation
Sample collection
Sample transportation
Sample preparation
And sample storage
Error while taking the swab

- Corrective action:

1) Use freshly collected specimens for optimal test performance. Inadequate specimen collection or improper sample handling/storage/transport may yield erroneous results.

2) For optimal performance, use the swabs provided in the test kit. Alternatively, foam, polyester, Hydra Flock And nylon flocked throat swabs can be used to collect throat swab samples.

3) Rayon swabs and the BBL Culture swab Liquid Stuart transport media system are not suitable for use in this assay.

4) Collect patient specimen by swabbing the posterior pharynx, tonsils and other inflamed areas. Avoid touching the tongue, cheeks and teeth with the swab.

- Post analytical errors:

Uncontrolled result
Wrong test done on specimen
Not all requested tests done.