Widal Test (Slide Agglutination)

Also known as Typhoid test (Slide agglutination)

You need to provide

Blood

This test is for

Male, Female

Understanding Widal Test (Slide Agglutination)

What is Widal Test (Slide Agglutination)?

A Widal Test (Slide Agglutination) helps detect typhoid fever and paratyphoid fever, collectively known as enteric fever, by identifying the antibodies against two antigens (O & H) of typhoid-causing bacteria, Salmonella typhi. Early detection of enteric fever is crucial to prevent serious complications like intestinal bleeding or perforation.

Enteric fever is a life-threatening disease caused by the bacteria Salmonella enterica serotype Typhi (S. typhi). It is usually transmitted through food and drinks contaminated with fecal matter. The most common symptoms of typhoid include high fever, headache, fatigue, diarrhea or constipation, a specific rash called rose spots, abdominal pain, and weight loss. They may be noticed about 1 to 2 weeks after being infected.

You may need a Widal Test (Slide Agglutination) if you have traveled to areas where the infection is present, or if you have been in close contact with someone who has traveled to the infected areas or is infected. Individuals close to the infected person should also get tested to rule out the possibility of infection transmission. No special preparation is needed for a typhoid test; eat or drink as per your daily routine. However, talk to your doctor about all the pre-test instructions.

Test result ranges are approximate and may differ slightly between different labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. Narrate your complete medical history to help the doctor correlate your clinical and laboratory findings. The test results will help them determine your medical condition, make recommendations for lifestyle modifications such as diet and exercise, decide whether or not medication will be required to manage your condition, and formulate your overall treatment plan.

What is Widal Test (Slide Agglutination) used for?

A Widal Test (Slide Agglutination) is done:

To detect typhoid fever.

What does Widal Test (Slide Agglutination) measure?

A Widal Test (Slide Agglutination) helps detect antibodies in the blood against typhoid-causing bacteria called Salmonella typhi.

Interpreting Widal Test (Slide Agglutination) results

Interpretations

If the antibody against Salmonella is present in the patient’s serum, it will react with the respective antigen in the reagent and give visible agglutination (clumping) on the test slide.

The highest dilution of the patient’s serum sample that gives a visible agglutination with the Widal test antigen suspensions is the antibody titre.

The serum sample which shows the titre of 1:80 or more for O agglutination and 1:160 or more for H agglutination indicates active infection. A rise in titres (4-fold or more) in the two blood samples taken 10 days apart confirms the diagnosis. Please note that different labs may have different reference values for the interpretation of the Widal test.

The interpretation of a Widal test is greatly influenced by the nature and extent of the patient’s previous contact with typhoid antigens. It can be either due to clinical or subclinical infection with typhoid or related organisms or from typhoid vaccination. The lesser the extent of the previous contact, the greater is the usefulness of the Widal test.

Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Widal Test (Slide Agglutination)

Frequently Asked Questions about Widal Test (Slide Agglutination)

Q. How is a widal test performed?

A doctor will clean the skin using an antiseptic alcohol cotton swab or wipe and take out a blood sample from your veins using a needle. The blood sample will be stored safely and transported to the lab for analysis.

Q. Is there any risk associated with a widal test?

There is usually no risk associated with this test. However, some people may feel a slight sting when a needle is pricked and may experience some bleeding that is normal and usually not bothersome. Rarely some people may also experience slight swelling or bruising at the site of the needle prick. Applying ice 3-4 times a day for about a week may help reduce swelling and bruising. If it does not get better, consult your doctor.

Q. How does typhoid spread?

Typhoid spreads by consuming food or water contaminated with Salmonella typhi. You can also get infected if someone infected with typhoid touches your food without washing their hands. People who drink contaminated water or eat food washed in contaminated water can develop typhoid fever. Some other ways via which typhoid fever can be contracted include using a toilet contaminated with bacteria, touching your mouth before washing your hands, eating seafood from a water source contaminated by infected body wastes, eating raw vegetables that have been fertilized with human waste, contaminated milk products, and engaging in oral or anal sex with a person who's a carrier of Salmonella typhi bacteria.

Q. How can I prevent typhoid fever?

Avoiding contaminated foods and drinks can help to prevent typhoid fever. While traveling to an infection-prone area, drink only bottled or boiled water, eat properly and hygienically cooked food, and avoid eating seafood or salads. Additionally, getting vaccinated against typhoid fever can also prevent it.

Q. How long will it take for me to recover from typhoid?

You will start feeling better within a few days, 3 to 5 days, of starting the treatment. However, without any treatment, it can take weeks or even months to fully recover, and the symptoms may return.

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