Doctors can perform a strep throat culture on an individual to see if the person has it. How it is done is the doctor takes a swab and scrapes the infected area in the throat, usually on the tonsils. The swab is then sent to the lab for analysis. There is a rapid strep test available that can detect the strep within a matter of minutes.
Please remember that a strep culture is not always necessary when determining if an individual has strep or not. Strep is characterized by white pus filled spots on and around the tonsils. In addition, a person does not need to have tonsils to get strep. I had strep throat about two months ago and had a tonsillectomy about eight years ago. The strep did attach itself to left over lymph tissue in my throat.
A common antibiotic to give a person who has strep throat is amoxicillan.