Introduced by F. Widal in 1896, the Widal test is a blood test that measures antibody titres to diagnose typhoid or paratyphoid fever (collectively as enteric fever). Antibody titres assess the immune response of the body by measuring particular antibodies in the blood in reaction to antigens (foreign substances). The Widal test detects antibodies against the O and H antigens of Salmonella Typhi and the H antigens of Salmonella Paratyphi . The test uses a suspension containing killed Salmonella Typhi bacteria as the antigen to identify typhoid fever in febrile patients. Thus, those with symptoms of enteric fever may benefit from a Widal test.

Given its role in diagnosing enteric fever, the Widal test can be a critical diagnostic tool aiding in timely detection and treatment. Therefore, consider getting a Widal test in Noida today, if you live in Noida and are experiencing symptoms of enteric fever.

Consider the following factors, before booking the Widal test in Noida:

Prerequisites

Fasting is not required for the Widal test.

Best Time to Get Tested

You can get the Widal test at any time throughout the day.

Who Should Get a Widal Test

If someone has been in a high-risk area for typhoid or paratyphoid fever and is experiencing headache, fever, fatigue, and gastrointestinal issues (constipation, diarrhoea, or abdominal pain), they should consider getting a Widal test.

Cautions Before Taking the Widal Test

There are no special precautions necessary for this test.

The incubation period for typhoid bacteria typically ranges from 6 to 14 days, although it can extend to 30 days. This is the interval of time between the start of symptoms and bacterial infection. For paratyphoid bacteria, the incubation period ranges from 1 to 10 days. Generally, during the course of 3 to 4 days, symptoms often become worse.

A doctor might order a Widal test if you have symptoms of typhoid fever. Similar, but milder, symptoms occur with paratyphoid fever. These signs and symptoms include:

• High fever or chills

• Constipation

• Diarrhoea

• Feeling unwell, weak, or sick

• Headache

• Extreme fatigue

• Pain in the abdomen

• Sweating

• Blood in the stool

• Sore throat and persistent cough

• Bleeding from the nose

• Weight loss

• Loss of appetite

• Red rash on the chest and abdomen

• Confusion or hallucinations

• Difficulty in concentrating

• Decreased heart rate

• Poisoning of blood

• Enlarged spleen or liver

Please note: Even with vaccination, 20–50% of individuals may still contract typhoid upon exposure, indicating incomplete immunity.

A Widal test might be suggested for those at increased risk, including:

• People in close proximity to an infected person.

• Young children, who are more at risk for these diseases than adults.

• Travellers to regions where typhoid and paratyphoid are widespread, such as India, Bangladesh, the Middle East, and Africa.

Below is a breakdown of the results of the Widal test:

Interpretation

Titres below 1:80 are considered negative, indicating no infection is present.

Titres at or above 1:80 are generally seen as positive, though this threshold may differ across various populations and regions. A rising titre, identified through multiple samples taken at 4- to 6-day intervals after disease onset, is more significant than just one high titre. To reach a final diagnosis, test results should be correlated with the patient’s medical history.

Limitations

Patients who have been vaccinated against typhoid may show elevated antibody titres, which could lead to false-positive results. Similarly, individuals with past infections or vaccinations may also have misleading results.

Agglutinins generally appear by the end of the first week of infection, so blood samples taken earlier might produce negative results.

Though the serological findings of this test are important, they should not replace culture-based methods for identifying the causative organisms. Culture and biochemical tests should be performed to recover and identify the pathogens.