Tonsillitis: Symptoms and the Lab Tests Behind Them

Learn about the symptoms of tonsillitis and the lab tests that help diagnose this common condition.

Sep 11, 2026 3 min read

Tonsillitis is an inflammation of the tonsils, which are two lymph nodes located at the back of your throat. This condition is common, especially in children, and can be caused by viral or bacterial infections. Understanding the symptoms and the lab tests used to diagnose tonsillitis can help you manage this condition effectively.

What is Tonsillitis?

Tonsillitis occurs when the tonsils become infected and swollen. The tonsils are part of the immune system and help fight off infections. When they become inflamed, it can lead to a sore throat, difficulty swallowing, and other uncomfortable symptoms. Tonsillitis can be caused by various viruses, such as the common cold or flu, or by bacteria like Streptococcus, which is responsible for strep throat.

Have your own lab results? Upload your report and get a clear, private AI explanation in minutes - free, in English, Russian or Hebrew.
Analyze my results

Symptoms of Tonsillitis

The symptoms of tonsillitis can vary depending on whether the infection is viral or bacterial. Common symptoms include:

Lab Tests for Diagnosing Tonsillitis

To diagnose tonsillitis, doctors may perform a physical examination and review your symptoms. They may also recommend lab tests to determine the cause of the infection. Common tests include:

  • Throat Swab Test: This involves taking a sample from the back of your throat to check for the presence of bacteria such as Streptococcus. This test helps determine if antibiotics are needed.
  • Complete Blood Count (CBC): A CBC can help identify if the infection is viral or bacterial by measuring the number of white blood cells, which increase in response to infections.
  • Rapid Antigen Test: This test quickly detects the presence of Streptococcus bacteria and can provide results in minutes.

Treatment Options

Treatment for tonsillitis depends on the cause of the infection. If the tonsillitis is caused by a virus, it usually resolves on its own with rest, hydration, and over-the-counter pain relievers. For bacterial tonsillitis, antibiotics may be prescribed to help clear the infection. In recurrent or severe cases, a doctor might recommend a tonsillectomy, which is the surgical removal of the tonsils.

Frequently Asked Questions

Is tonsillitis contagious? Yes, tonsillitis can be contagious, especially if caused by a viral or bacterial infection. It can spread through respiratory droplets when an infected person coughs or sneezes.

Can adults get tonsillitis? Yes, while it is more common in children, adults can also develop tonsillitis.

How long does tonsillitis last? Viral tonsillitis usually lasts about 7 to 10 days, while bacterial tonsillitis may improve within a few days of starting antibiotics.

What are the complications of untreated tonsillitis? If left untreated, tonsillitis can lead to complications such as an abscess around the tonsils, middle ear infections, or more serious infections like rheumatic fever.

When to See a Doctor

You should see a doctor if you experience severe symptoms such as difficulty breathing, extreme difficulty swallowing, or if your symptoms persist for more than a few days without improvement. Also, if you have recurrent episodes of tonsillitis, it is important to consult a healthcare provider.

Decisions about your health should always be made in consultation with your healthcare provider.

Read this in another language

Doctor reviews: 0 - pending

This explainer is queued for our doctor panel and hasn't been individually reviewed yet. It's general information, drawn from standard references - always confirm decisions with your own clinician.

Have your own lab results? Upload your report and get a clear, private AI explanation in minutes - free, in English, Russian or Hebrew.
Analyze my results