Throat Culture - Strep TestingThroat Culture or Strep Test A throat culture or strep test is performed by taking a sample with a swab from the back of the throat to identify group A streptococcus bacteria, the primary cause of strep throat. These bacteria can also lead to other conditions such as scarlet fever, abscesses, and pneumonia. The sample is cultured on a special medium in the lab, allowing any bacteria present to grow. If no bacteria grow, the culture is considered