What is a widal test used for?

If you are having symptoms of high fever, fatigue, diarrhoea, constipation, abdominal pain, rashes known as rose spots, dry cough, and headache, there is a probability of typhoid fever. Doctors suggest Widal test in the diagnosis of typhoid fever.  Salmonella enterica serotype typhi bacteria cause typhoid fever. The infection occurs due to the consumption of contaminated food and water with faecal matter. Widal test means to detect typhoid causing bacteria in the bloodstream of the patient through the agglutination biochemical test.

Often, people search for the full form of Widal. The fact is, Georges Ferdinand Widal developed the test, and so the name of the test is called the Widal test after him. A Widal test is used to investigate the presence of H and O serum agglutinins in the patient’s serum.

How is the Widal test for Typhoid performed?

Widal test procedure involves the serum agglutination test to detect typhoid fever. Patients who are suffering from enteric fever will carry homologous antibodies in the serum. The slide method and the tube method are the two types of Widal test procedures. If the serum reacts with the respective antigen, agglutination will happen. Widal test for typhoid is a rapid test diagnostic method, and results are ready on the same day.

What is the Widal test results  range?

The interpretation of the Widal test reports  needs careful study. Widal blood test is both qualitative and quantitative diagnostic analysis. A Widal test report is more commonly known as the typhoid test report. If the Widal test range is more than or equal to 1:160 titre for antigen O and antigen H, then it indicates  typhoid infection. For the diagnosis of a Widal blood test, 1:20, 1:40, 1:60, 1:80, 1:160, and 1:200 titres need to be included in the diagnosis to obtain the typhoid test report.

What is the Widal test normal range chart?

When the test report lies in the Widal test normal range chart, then it is negative for the typhoid fever. If the titre value is less than or equal to 1:20, 1:40, 1:80, and less than 1:160 in the test report, then the typhoid test result lies in Widal test normal value.

What are the Widal test positive values?

Widal test positive values indicate  that the person has the Salmonella enterica serovar typhi bacterial infection. In the typhoid report positive, both O and H antigen titres are present. S typhi O positive means active infection of typhoid fever. Active infection indicates the patient has an infection of Salmonella enterica serovar typhi. S typhi H positive means there is a past infection or it shows the result of the immunized person’s serum test report.

What is Widal test negative?

Widal test negative means that a person does not have enteric fever, and there is another infection causing the symptoms. The titre value of antigen O and H is below 1:160 in the sample.