What does the test measure?
Typhoid fever, also called enteric fever, is a life-threatening infection caused by the bacterium Salmonella Typhi, present in animal and human intestines, that is passed via faeces and urine. A person with typhoid fever is contagious since an infected person can pass the bacteria out of their body through pee and poo. Someone eating food or drinking water that has been contaminated with the faeces of a person who has been infected with the bacteria Salmonella typhi, can become infected resulting in developing typhoid fever. The fever is associated with symptoms that include high fever, diarrhea, fatigue, headache, abdominal pain, weight loss, and a rash known as “rose spots.” To make a precise diagnosis, samples of blood, poop or urine are required to be analysed.
What is the Widal test used for?
A Widal test is a blood test that may confirm or rule out typhoid fever when the symptoms first appear. The test is used to find out antibodies against flagellar (H) and somatic (O) antigens that cause infection and typhoid fever. The test evaluates the interaction between these antigens and antibodies found in the blood samples of patients. It helps diagnose a current or recent infection or to determine if an individual has had a previous typhoid infection. The test is recommended to be conducted in the first week of the infection because the antibody testing against “O” and “H” antigens of Salmonella starts appearing in serum at the end of the first week of the fever. The incubation period – the time interval between exposure to an infection and the appearance of the first symptoms of typhoid fever – is 6–30 days.
Who should get tested?
Typhoid fever can result in health complications if it is not addressed properly. If an individual exhibits these symptoms, a doctor may recommend a widal test to confirm the diagnosis:
Fever and aches: A patient suffering from typhoid fever witnesses a significant rise in body temperature, frequently reaching temperatures of 103 to 104 degrees Fahrenheit. The fever can endure for multiple days, accompanied by symptoms such as headaches and general body discomfort.
Gastrointestinal symptoms: Individuals with typhoid fever may witness abdominal unease, pain, and sensitivity. While in the initial stage, constipation is observed, but as the illness progresses, diarrhea may manifest.
Red spots on the body: The body’s trunk or other regions may display the presence of rosy-hued spots. When pressure is applied to these spots, they may fade and then reappear.
Drop in appetite and energy levels: Typhoid fever may result in a loss of appetite, causing weight loss. Patients may feel weak and exhausted and may have difficulty performing daily activities.
Mental Symptoms: The presence of typhoid fever can result in a decrease in appetite, potentially leading to weight loss. The patients may experience feelings of weakness, exhaustion and find it challenging to carry out their regular daily tasks.
How is it performed?
There are no special preparations required for this test, and no fasting is needed. A blood sample is taken by inserting a thin needle into a vein in the arm. This sample is subsequently sent to a laboratory for analysis.
Widal test price may vary depending on the location of the lab,
Understanding test ranges and results:
Interpreting the results will require a thorough and precise analysis of the titer values. The following titers are considered significant for diagnosing typhoid fever: 1:20, 1:40, 1:60, 1:80, 1:160, and 1:200.
Negative Result – A negative result happens when the titer values for both O and H antigens are less than 1:160. This negative result falls within the normal range for this test.
Positive Result – A positive result is indicated when the titer values for O and H antigens range from 1:60 to 1:320. A positive test result suggests the presence of Salmonella typhi in the bloodstream.
The test serves as a quick and cost-effective method for screening typhoid infection, particularly in areas where access to medical facilities may be limited or restricted.
Disclaimer: For personalised advice and further information, always consult your doctor or qualified healthcare professional.