Widal Slide

Now, the purpose of The Widal Slide Test is to diagnose Typhoid and para typhoid fevers. George Fernand Widal invented this test in 1896. The test aims to look for antibodies that fight Salmonella Typhi and Paratyphi in blood or serum sample. These antibodies are made by the immune system in response to the infection. This test is based on the principle of agglutination. Patient’s serum is mixed with killed Salmonella antigens on a slide. If the patient has antibodies against Salmonella, these antibodies will react with the antigens leading to clumping of the Salmonella and forming visible aggregates meaning the test is positive. 

This test measures the agglutination reaction of the patient serum and Salmonella. It helps determine the strength of antibodies directed against Salmonella Typhi and Paratyphi. Agglutination is measured by the dilution of the serum that gives positive agglutination following the highest dilution. 

The Widal Slide Test is usually taken when a person has symptoms of either typhoid or paratyphoid fevers like: 

1. Fever lasting longer than normal 

2. Headaches 

3. Abdominal pains 

4. Diarrhoea or even constipation 

5. Extreme tiredness 

The test is suggested even if an individual is in proximity with another individual who suffers from Typhoid or paratyphoid fever. 

Widal Slide Test is a relatively easy and safe test. However, there are certain limitations and risks that are attached to the use of the Widal Slide Test: 

1. There is a risk of false positives to schedules of other infections such as malaria and tuberculosis due to the producing antibodies. 

2. Patients with a scheduled dose of antibiotics or immunocompromised state could be negative. 

3. This test should not be conducted on patients with certain health issues like serum sickness or rheumatoid arthritis. 

The Widal Slide Test checks for the following parameters: 

1. O (somatic) antigen detects antibodies against the cell wall of Salmonella Typhi and Paratyphi. 

2. H (flagellar) antigen: detects antibodies against the flagella of Salmonella Typhi and Paratyphi. 

3. AH (anti-H) antigen: detects antibodies against the flagella of Salmonella Paratyphi. 

Medical professionals look for agglutination reactions against these antigens to determine the present level of antibodies. 

The Widal Slide Test is usually required for: 

1. People having signs of typhoid or paratyphoid fever 

2. People in close relation to someone suffering from typhoid or paratyphoid 

3. Anyone who has travelled to regions where typhoid or paratyphoid fever exists 

Widal Slide Test might be useful for patients suffering from typhoid and paratyphoid fever because this test empowers the specialist to treat patients in a timely manner and can help prevent complications. Also, the test is helpful to trace the infection's carrier, and that is very important not to let the spread of the disease. 

Widal Slide Test is capable of diagnosing: 

1. Typhoid fever 

2. Paratyphoid fever 

3. Carrier state of either of the two mentioned above 

The Widal Slide Test has no specific preparations. Nevertheless: 

1. Patients are advised to stop taking any antibiotics or other medicines that would alter the outcomes of the test 

2. Patients should undergo fast – no food or drink – for at least 8 hours before the test. 

3. Before the test, patients are required to cough up relevant information related to medications or diseases that could affect the outcome of the test. 

4. Patients are required to abstain from eating or drinking anything 8 hours prior to taking the test. 

Prerequisites: 

1. A patient’s serum or blood sample is needed. 

2. A healthcare professional or a laboratory can conduct the test. 

Eligibility: 

1. The test is designed for patients of geriatric and paediatric age groups.  

2. Patients diagnosed with rheumatoid arthritis or serum sickness will not be eligible for the test. 

Procedure For Taking the Test: 

1. A medical assistant obtains a blood sample from a selected area located on the arm which contains a vein. 

2. The vial containing the blood sample is labelled and dispatched to the relevant medical laboratory for analysis. 

3. Results for the test take approximately one to two days while the window period is within 24 - 48 hours. 

Caution Before the Test: 

1. Patients should inform their healthcare provider about any medications or medical conditions that may affect the test results. 

2. Patients should avoid eating or drinking anything for at least 8 hours before the test.