Widal Tube Agglutination Test
About Widal Tube Agglutination Test
| Field | Value |
|---|---|
| Also Known As | Widal Test, Typhoid Test, Enteric Fever Test, Salmonella Agglutination Test |
| Sample Type | Venous blood (serum) |
| Fasting Required | No fasting needed |
| Report Time | Same day |
| Recommended For | All age groups and genders; anyone with symptoms of typhoid or paratyphoid fever |
| Price | Starting at ₹250 |
What Is a Widal Tube Agglutination Test?
The Widal tube agglutination test is a blood test that checks for antibodies produced by the body in response to a Salmonella infection. It is commonly ordered when a doctor suspects typhoid fever or enteric fever based on a patient's symptoms. A small blood sample is drawn from a vein, and the serum is tested in a laboratory. The test is also referred to as the typhoid fever test, enteric fever test or Salmonella agglutination test.
What Does a Widal Tube Agglutination Test Measure?
The test looks for specific antibodies in the blood against four Salmonella antigens. Here is what each parameter measures:
| Parameter | What It Detects |
|---|---|
| S. Typhi O (TO) | Antibodies against the bacterial cell wall; points to a recent or active infection |
| S. Typhi H (TH) | Antibodies against bacterial flagella (tail-like structures); may indicate a current or past infection |
| S. Paratyphi A (AH) | Antibodies against Salmonella Paratyphi A bacteria |
| S. Paratyphi B (BH) | Antibodies against Salmonella Paratyphi B bacteria |
Why Is a Widal Tube Agglutination Test Done?
A doctor may order this test when a patient presents with symptoms that suggest a possible Salmonella infection.
Common Symptoms That May Require This Test
The following symptoms are among the most common reasons a doctor orders a typhoid test:
- Prolonged or persistent fever
- Generalised fatigue and weakness
- Headache
- Nausea or loss of appetite
- Abdominal pain
- Constipation or diarrhoea
- Small red spots (rose spots) on the abdomen or chest
Conditions This Test Can Help Detect
This enteric fever test can help identify the following conditions:
- Typhoid fever, caused by Salmonella enterica serotype Typhi
- Paratyphoid fever, caused by Salmonella enterica serotypes Paratyphi A or Paratyphi B
- General enteric fever, as part of initial screening
How to Prepare and What to Expect
Preparing for this test is straightforward, and the process is quick and simple.
Do You Need to Fast?
No, fasting is not required for the Widal tube agglutination test. You can eat and drink normally before giving your sample. However, always follow the instructions given by your doctor or the diagnostic centre at the time of booking.
Practical Tips Before Your Test
Keeping a few things in mind before your visit will help ensure an accurate result:
- Inform your doctor about any antibiotics or other medications you are currently taking, as these can affect antibody levels
- Mention if you have previously received a typhoid vaccination, as this may raise antibody levels
- Drink adequate water before your appointment
- Wear clothing with sleeves that can be rolled up easily
Step-by-Step Procedure
Here is what to expect during sample collection:
- A trained phlebotomist will ask you to sit comfortably and extend your arm.
- A small area on your inner arm will be cleaned with an antiseptic.
- A fine needle is used to draw a small blood sample from a vein; the process usually takes no longer than five minutes.
- The sample is collected in a sterile tube and labelled.
- In the laboratory, your serum is mixed with Salmonella antigens; if antibodies are present, visible clumping (agglutination) appears at the bottom of the test tube.
- The degree of clumping is measured and reported as an antibody titre.
Factors That Can Affect Accuracy
Several factors may influence your test result. Your doctor should be aware of the following:
- Prior typhoid vaccination can cause elevated antibody levels
- Recent or ongoing antibiotic use may reduce antibody response
- Testing too early in the illness (before 7 days of fever) may give a false-negative result
- Conditions such as malaria, chronic liver disease, immunological disorders, and cryptococcal meningitis can cause false-positive results
- The prevalence of typhoid in your local area can influence baseline antibody levels
Understanding Your Widal Tube Agglutination Test Results
Your results are reported as antibody titres for each of the four parameters. A higher titre means more antibodies were detected. Always review your results with your doctor.
| Parameter | Normal Range | Possible Significance if Elevated |
|---|---|---|
| S. Typhi O (TO) | Below 1:80 | Titres of 1:80 or higher may point to an active infection |
| S. Typhi H (TH) | Below 1:160 | Titres of 1:160 or higher may indicate a current or past infection |
| S. Paratyphi A (AH) | Below 1:80 | Elevated levels may suggest paratyphoid A infection |
| S. Paratyphi B (BH) | Below 1:80 | Elevated levels may suggest paratyphoid B infection |
A confident diagnosis of enteric fever is typically supported by a fourfold or greater rise in titres across two blood samples taken ten days apart.
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Certain medical situations can make results harder to interpret. Antibody levels may be elevated in patients with other bacterial infections, including those caused by E. coli, Klebsiella, or S. aureus, not just Salmonella. Patients with malaria have also shown raised Salmonella O and H titres without typhoid infection. A previous typhoid vaccination can elevate H antibody levels even in the absence of current infection. Your doctor will factor in these possibilities when reading your results.
How to Maintain Healthy Levels
Preventing typhoid infection largely comes down to hygiene and food safety. Consider these general wellness practices:
- Drink only clean, filtered, or boiled water, particularly in areas where typhoid is common
- Wash hands thoroughly with soap before meals and after using the toilet
- Avoid raw or uncooked food from sources where hygiene standards may be poor
- Ask your doctor about typhoid vaccination if you are travelling to a high-risk area
Lupin Diagnostics Widal Tube Agglutination Test Price and Home Collection
The Widal tube agglutination test is available at Lupin Diagnostics, with prices starting at ₹250 across cities. Here is a table showing the approximate cost in major cities:
| City | Approximate Price ( ₹) |
|---|---|
| Hyderabad | ₹300 |
| Mumbai | ₹350 |
| Bengaluru | ₹250 |
| Chennai | ₹450 |
| Kolkata | ₹350 |
| Pune | ₹350 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home sample collection for the Widal tube agglutination test across multiple cities, so you do not need to visit a centre if that is more convenient. All samples are processed in NABL-accredited laboratories by trained professionals. Your digital report is delivered via email or WhatsApp once ready.
Frequently Asked Questions
The Widal tube agglutination test is used to detect antibodies in the blood that the body produces when infected with Salmonella Typhi or Paratyphi bacteria. It is a widely used, affordable test for diagnosing typhoid fever and paratyphoid fever. Doctors often order it when a patient has a prolonged fever with no obvious cause.
Results are usually available on the same day the sample is collected, typically within 12 to 24 hours. In some cases, it may take slightly longer depending on the laboratory's workload. You will receive your report digitally once it is ready.
No fasting is needed. You can eat and drink normally before giving your blood sample. However, if your doctor has ordered other tests at the same time, those may have different requirements, so it is best to confirm with your doctor beforehand.
A positive result means the body has produced antibodies against Salmonella Typhi. A titre of 1:80 or higher for the O antigen and 1:160 or higher for the H antigen is generally considered positive for typhoid fever. However, your doctor may ask for a repeat test or a blood culture to confirm the diagnosis before starting treatment.
Yes, both false-positive and false-negative results are possible. False positives can occur due to prior typhoid vaccination, malaria, chronic liver disease, and certain other bacterial infections. False negatives may occur if the test is done too early in the illness or if the patient has been taking antibiotics. This is why the enteric fever test should not be used in isolation and is best interpreted alongside other tests.
The test is most reliable after the first week of fever. The body typically takes 7 to 10 days to produce detectable levels of antibodies, so testing too early may give an inaccurate result. If initial results are inconclusive, your doctor may ask for a repeat test on a second sample collected around ten days later.
Yes, the test involves a routine blood draw and is safe for all age groups, including children. There may be mild discomfort or slight bruising at the needle site, but this usually resolves quickly on its own.
Widal Tube Agglutination Test
