✍️ Written by the MedTestBD Editorial Team · Last reviewed: July 2026
What is the Widal Test?
The Widal test is a blood test used to help diagnose typhoid fever, which is caused by the bacteria Salmonella typhi. It detects antibodies that the body produces in response to a typhoid infection. The test is widely used in Bangladesh and other South Asian countries where typhoid is common, particularly during the rainy season.
Why is the Widal Test Done?
- To investigate prolonged fever (more than 5–7 days) that may be caused by typhoid
- To support the diagnosis of typhoid fever when a blood culture is not available
- To differentiate typhoid from other causes of fever such as dengue or malaria
- To confirm treatment response in patients already diagnosed with typhoid
Normal Widal Test Results
| Antibody | Significant Titre (Single Sample) |
|---|---|
| O Antigen (Salmonella typhi) | 1:80 or above is considered significant |
| H Antigen (Salmonella typhi) | 1:160 or above is considered significant |
A positive Widal result alone does not confirm typhoid — the titre must be interpreted alongside symptoms, fever duration, and the patient's vaccination history. A single test can give false positives. Doctors often repeat the test after 5–7 days looking for a rising titre, which is more meaningful than a one-time result.
How to Prepare for the Widal Test
- No fasting is required for this test
- Inform your doctor if you are currently taking antibiotics — they can reduce antibody levels and affect the result
- Inform the doctor if you have had a typhoid vaccine recently, as it can cause a false positive
- A simple blood sample is drawn from a vein in your arm
- The test is most reliable when done after at least 5–7 days of fever
Widal Test Price in Bangladesh
Widal test prices vary between diagnostic centers across Bangladesh. Compare Widal test prices on MedTestBD →
⚠️ This information is for general reference only. Always consult a qualified physician before undergoing any medical test.
