Health guide
Widal test for typhoid: how it works and what results mean
The Widal test looks for antibodies your body makes against the bacteria that cause typhoid and paratyphoid fever. It is widely used in India to investigate a prolonged fever, but its result needs careful interpretation: timing matters, and both false positives and false negatives happen. It is a useful first step, not the final word.
Reviewed by Dr. Vishal Singh, Lab Director
When to consider a typhoid test
- A fever lasting more than three to four days
- A fever that climbs steadily, often worse in the evening
- Headache and body ache
- Abdominal pain and loss of appetite
- Weakness and tiredness
- Constipation or loose motions
How to read a Widal result
Results are reported as titres against O and H antigens (for example 1:80, 1:160). A single high titre, or a clear rise across two samples taken about a week apart, supports typhoid. A test done very early in the illness can be falsely negative because antibodies take days to build up.
Its limits and what doctors add
The Widal test alone is not enough to confirm typhoid: past infection, vaccination, and other illnesses can make it falsely positive, and timing can make it falsely negative. Doctors read it with your symptoms and may add a blood culture, which is the more definitive test. Always start treatment under medical advice.
This guide is for general information and is not a diagnosis. Always discuss your symptoms and results with a doctor. LabONE includes a free doctor consultation with every report.
Frequently asked questions
Can a Widal test be falsely positive?
Yes. A past typhoid infection, typhoid vaccination, or some other infections can raise the titres without current typhoid. This is why doctors interpret it alongside symptoms and, often, a blood culture.
When should I do a Widal test?
It is usually more reliable after the first several days of fever, once antibodies have had time to rise. Your doctor will advise on timing and whether a repeat or culture is needed.
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