Widal Test for Typhoid Fever – A Brief Introduction

Widal test is named after a French physician, Georges Ferdinand Widal, who first conducted it in 1896. This test is an advanced method of taking a blood test to detect typhoid fever in the body. Typhoid fever is a bacterial infection that spreads through the consumption of contaminated food or water. Here is a brief introduction to a widal test for typhoid fever.

Widal test for Typhoid Fever

Typhoid fever is caused by bacteria called salmonella that enters the body when a person consumes contaminated food or water. The incubation period for the signs and symptoms to appear in a person after exposure to the infection is between 6 to 30 days.

The main purpose for conducting a widal test is to diagnose typhoid or enteric fever and to check for the O and H antibodies in an individual’s body that fight against salmonella. A blood sample is drawn to conduct this test and the interaction between the antibodies and antigens is analysed. If the presence of these antibodies is detected, then it is possible that the person has typhoid fever.

Who Should Get Tested

These are several symptoms of typhoid fever, and if the person has these, they should get tested at a reputed pathology lab. The symptoms for typhoid or enteric fever are as follows: ​

• High fever
• Abdominal pain, constipation, or diarrheic
• Red spots on the abdomen/chest
• Headaches/ body aches 
• Loss of appetite 
• Fatigue
• Blood in the stool
• Chills
• Difficulty concentrating 

Normal Range of a Widal Test

Different pathology labs have different normal ranges of a widal test. This is why it is suggest consulting a health care provider and asking them about the test results. Generally, when the titre value is between 1:20 to 1:60, the widal test result is normal. Titre value equal to or higher than 1:160 indicates a positive result. A positive test result means that the person is infected with salmonella and has typhoid fever.The price for a widal test is different at different pathology labs; it can differ based on location, pathology lab, and other criteria. It is recommended to get a widal test done if a person has the above-mentioned symptoms.