Widal test is one way to diagnose typhus. This examination is still widely carried out in Indonesia because it is practical, fast, easy, and inexpensive.
Typhus is also known as typhus or typhoid fever. Of the 11-20 million typhus cases per year in the world, Indonesia along with other countries in Southeast Asia have the most typhus cases. This disease is characterized by fever accompanied by indigestion, such as constipation or diarrhea.
The Widal Test Function for Typhus Diagnosis
Typhus is caused by Salmonella bacterial infection. This bacterium can be found in foods that are not cooked well, or not processed hygienically.
When Salmonella bacteria enter the human body, the body's defense system will respond by producing special antibody substances to fight Salmonella bacteria. A Widal test is performed to determine the amount of the antibody. An increase in the number of these antibodies can indicate typhus.
How to Do and Read Widal Tests
When symptoms are suspected as a result of typhus, the first stage of diagnosis by the doctor is to trace the history of the disease. The doctor will ask about the cleanliness of food and shelter, as well as the history of complaints that arise.
Then the doctor will do a physical examination, including checking body temperature, looking at the surface appearance of the tongue, checking which part of the stomach hurts, and listening to the sounds of the intestine.
To determine whether the patient has typhus, one type of test that can be recommended by doctors is the Widal test. In the Widal examination, the patient will be asked to undergo the process of taking blood. After that, blood samples will be sent to a laboratory for examination.
In the laboratory, blood samples will be dropped with Salmonella bacteria that have been turned off in the form of O antigens (bacterial bodies) and H antigens (tail or bacterial flagellum). Both of these test materials are needed because the antibodies for the bacterial body and the bacterial flagellum are different.
Furthermore, blood samples are diluted dozens to hundreds of times. If after being diluted many times, antibodies against Salmonella prove to be positive, the patient may be considered to have typhoid or typhus fever.
However, the standard reading of these tests varies in different regions, depending on the endemic level of typhus in that region. In Indonesia, widal readings can generally be regarded as strong data to support the diagnosis of typhus, when Salmonella antibodies are still found at dilution 320 times (1: 320) or more.
The diagnosis of typhus can be confirmed through a repeat Widal test, which is done 5-7 days after the first test. The patient tested positive for typhus when the amount of Salmonella antibodies increased to four times compared to the first test.
Are the Widal Accurate Test Results?
The Widal test is actually quite accurate, but there are a number of factors that can influence its level of accuracy. Some of these include the quality of blood samples and antigens used, or the way the tests are examined and the reading of test results.
In addition, someone can get positive results on the Widal test even if they don't have typhus. This can happen if the patient is a carrier (carrier) of the bacteria that causes typhus or recently did typhus vaccination. People who have recently recovered from typhus can also get positive results, because antibodies to the Salmonella bacteria can remain in the body for up to two years.
On the other hand, negative Widal results also do not necessarily indicate a person does not suffer from typhus. This condition can occur due to poor nutrition, long-term consumption of drugs, or suffer from certain diseases that reduce endurance.
The Widal test is a quick and easy typhus diagnosis in areas with limited health facilities. However, in some cases, the Widal test can give false positive or false negative results.
For more accurate results, doctors can recommend other diagnostic tests, such as the TUBEX test, which can be done in a hospital or laboratory with adequate facilities. So if you experience typhus symptoms, do not hesitate to consult with your doctor so that an appropriate examination and treatment can be given.
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