Strep throat is a common bacterial infection caused by Streptococcus pyogenes, also known as Group A Streptococcus (GAS). While many sore throats result from viruses, a definitive diagnosis of strep throat requires specific testing. Untreated strep infection increases the risk of developing conditions such as acute rheumatic fever, which can potentially damage heart valves, or post-streptococcal glomerulonephritis, a form of kidney inflammation. Because symptoms like fever, sore throat, and difficulty swallowing can mimic other illnesses, testing is the only way to confirm the presence of GAS bacteria and begin the appropriate antibiotic treatment.
Primary Testing Locations
A person seeking a strep throat test has several options, each offering different levels of convenience, speed, and cost.
The traditional starting point is the Primary Care Physician (PCP) or pediatrician, who possesses a comprehensive medical history of the patient. However, obtaining an appointment with a PCP can sometimes involve a wait of a day or more, which delays diagnosis and treatment for an acute illness.
Urgent Care Centers are widely available, accepting walk-in patients for immediate, non-life-threatening concerns. These centers are equipped to perform necessary on-site testing and are staffed by medical doctors or advanced practitioners. Urgent care visits are typically more expensive than a routine office visit but offer extended hours and a much shorter waiting period than an emergency room.
Retail Health Clinics, often located inside major pharmacies or retail stores, provide an accessible option for simple illnesses. These clinics are generally staffed by nurse practitioners or physician assistants and offer the most affordable out-of-pocket cost for a simple strep test. While they provide high convenience and low cost, they may not be suitable for patients with complex medical issues.
The Emergency Room (ER) should be considered only if the sore throat is accompanied by severe symptoms, such as significant difficulty breathing, drooling, or an inability to swallow liquids. Using the ER for a routine strep test is the most expensive option and can result in extremely long wait times, as staff must prioritize life-threatening emergencies. For a straightforward strep test, choosing an urgent care center or retail clinic generally provides the best balance of speed, service, and cost.
Understanding the Testing Procedure
Diagnosing strep throat relies on identifying the Group A Streptococcus bacteria from a sample collected by swabbing the back of the throat and tonsils.
The initial test performed is usually the Rapid Antigen Detection Test (RADT), which provides results in minutes. The RADT works by detecting specific antigens on the surface of the bacteria, allowing for a quick determination of a positive result. While the RADT is highly specific, its sensitivity can be lower than other methods, leading to potential false negatives.
If the RADT is negative, a clinician may still suspect strep throat based on the patient’s symptoms. In these cases, a second test, called a throat culture, is often necessary to confirm the diagnosis.
The throat culture is considered the standard method for diagnosis because of its higher sensitivity. The swab sample is sent to a laboratory and incubated for 24 to 48 hours to allow any GAS bacteria present to grow. Guidelines recommend that all children and adolescents who test negative on a RADT receive a follow-up throat culture, as they face a higher risk of rheumatic fever if the infection is missed. For adults, a negative RADT is often sufficient, as the risk of this complication is significantly lower.
Treatment and Next Steps
Once a strep throat diagnosis is confirmed, treatment involves a course of antibiotics, typically penicillin or amoxicillin, which are highly effective against GAS bacteria. It is important to begin the medication promptly, as starting antibiotics within 48 hours of symptom onset can reduce the duration of symptoms and prevent the spread of the infection. Patients must take the full course of the prescribed antibiotic, usually lasting 10 days, even if symptoms disappear quickly.
Stopping the medication early increases the risk of the infection returning and, more significantly, raises the chance of developing serious complications like rheumatic fever. Symptom management can be addressed with over-the-counter pain relievers, such as acetaminophen or ibuprofen, to help reduce throat pain and fever. Gargling with warm salt water and consuming soothing foods and fluids can also help relieve discomfort.
Contagiousness decreases rapidly once treatment begins; a person is generally no longer considered contagious and can return to school or work 24 hours after starting the antibiotic and when they are without a fever. If a patient does not show improvement within 48 hours of starting the prescribed antibiotics, it is necessary to contact the healthcare provider for a re-evaluation.