Sore throats are among the most common reasons people visit urgent care — and the single most important question is always the same: is this strep, or is this viral? The answer changes everything, because antibiotics help with the first and do nothing for the second.
The Centor criteria: what we look at
Clinicians use a simple scoring framework called the Centor criteria to estimate strep probability before testing:
- Fever (or recent history of fever) — 1 point
- Swollen, tender anterior cervical lymph nodes — 1 point
- Tonsillar exudate (white patches on the tonsils) — 1 point
- No cough — 1 point
A score of 3–4 means high probability of strep — we test and treat if positive. A score of 0–1 is very unlikely strep — likely viral, no antibiotic indicated regardless of test result (we may still test for peace of mind).
The cough rule
This is the most practically useful single indicator: a sore throat WITH a cough is almost never strep. Cough suggests viral upper respiratory infection. Strep typically doesn't cause cough. If your throat hurts and you're coughing, the right treatment is rest, fluids, and symptom relief — not antibiotics.
Mono: the impersonator
Infectious mononucleosis (Epstein-Barr virus) can look exactly like severe strep — white patches, high fever, swollen nodes. A negative strep test in a teenager or young adult with these symptoms should trigger mono testing (monospot), because the management is very different and activity restrictions matter.
Why it matters to treat strep properly
Untreated strep very rarely causes rheumatic fever (heart valve damage) and post-streptococcal glomerulonephritis (kidney inflammation). These complications are the reason we treat — not just for symptom relief. A 10-day antibiotic course eliminates the risk and makes you non-contagious within 24 hours.
This article summarizes public health information. Always consult a licensed provider for personal medical decisions.
Frequently asked questions
Rapid antigen tests are about 95% sensitive and 98% specific. A positive result is very reliable. A negative result in a high-probability case (high Centor score) may prompt a backup throat culture, which is more sensitive.
Telehealth can assess probability and manage lower-risk cases, but the rapid test requires an in-person swab. We can do a telemedicine assessment and if strep is likely, direct you for in-person testing with an expedited process.
