Typhoid Fever Can Be Confirmed by Which Test?

What is Typhoid?

Typhoid fever is one of the most serious bacterial diseases caused by Salmonella Typhi. Although contaminated foods and contaminated water sources usually propagate it. This disease poses a significant health problem for developing nations, with an incidence estimated at 11-20 million^[1] cases on its central recognition by the World Health Organization (WHO). Therefore, Early diagnosis and treatment should be initiated immediately. This article discusses the specific tests used to confirm typhoid fever. Additionally, it provides a comprehensive overview of how such tests help identify the disease while managing the 4 stages of typhoid fever.

Understanding the 4 Stages of Typhoid Fever

It progresses through 4 stages of typhoid fever, the last of which is the worst that could possibly occur. Moreover, below are the symptoms for each stage: 

•  1: Mild fever with fatigue and a mild upset stomach.
•  2: High fever, stomach pain complaints, and no desire to eat.
•  3: Serious complication with bleeding or perforation of the intestines.
•  4: Serious infection enters the whole body, and organ failure is possible.

Before initiating early therapy, each 4 stages of typhoid fever must be adequately understood. Laboratory investigations confirm the diagnosis of the disease.

Below are the Tests That Confirm the Typhoid Fever

1. Widal Test: One of the Most Common Diagnostic Tests for Typhoid Fever

The Widal test is the most common diagnostic test for typhoid fever- the blood test for finding antibodies against Salmonella Typhi. It determines specific antigens O and H to confirm an infection.

Key Features:

• Validity: It has about 70%^[2] sensitivity and specificity, as supported by the study in the Indian Journal of Medical Research. However, it cannot be a reliable indicator in areas having seasonal typhoid infestations.
• Disadvantages: This could have caused false positive results because it cross-reacts with other infectious agents or previous vaccinations.

Read More: Vomiting in Winter and Illnesses: Symptoms, Causes, & Treatment

The Widal test diagnosis is applied, but incursion fails to be effective within the first 4 stages of typhoid fever, including the initial stage.

2. Typhidot Test: A Rapid Option

The Typhidot test is a veritable modern invention that aids in the detection of IgM and IgG antibodies indicating the presence of Salmonella Typhi, the organism responsible for typhoid fever. This test shows a faster and more reliable result than the Widal test.

Key Details:

• Speed: Result interpretation can be done in 1 to 3 hours, thus aiding in the early detection of typhoid fever.
• Accuracy: According to research, the test results are accurate between 85% and 95%^[3].
• Speciality: Typhidot test is especially recommended for early detection of infection. It’s prevalent in areas where typhoid fever is endemic.

This test will diagnose during the early stages, when other tests cannot, of all 4 stages of typhoid fever in reality.

3. Blood Culture: The Premier Test for Typhoid Fever

Blood culture is the superlative test in typhoid fever diagnosis; blood is taken from a patient to test for the presence of Salmonella Typhi and locate it.

Facts:

• Accuracy: The tests for detecting typhoid fever within the first week of infection are roughly 90%^[4] correct.
• Waiting for Results: This requires 24-72 hours for the results to be out, which does not allow it to be used in emergency situations.
• Relevance: Blood cultures help determine diagnosis and demonstrate drug-resistance strains of Salmonella Typhi. The procedure defines the infection in the bloodstream and gives insight into 4-stage typhoid fever in the treatment.

4. Bone Marrow Culture: Very Accurate in late stages

There are occasions when the presence and identification of Salmonella Typhi from a very small bone marrow sample are done immediately after blood culture fails.

Details:

• Accuracy: More than 95% sensitive even if the patient has already started antibiotics use are bone marrow cultures.
• Late Stage Use: This test is instrumental in diagnosis at the advanced stage of typhoid fever, where the bacterial load in the bloodstream is at its lowest. Bone marrow culture is an essential confirmatory test as one of the 4 stages of typhoid fever, particularly in cases complicated with intestinal perforation occurring in the third stage.

5. PCR (Polymerase Chain Reaction): A Modern Molecular Approach

PCR is indeed a state-of-the-art molecular tool for the accuracy of diagnostic findings such as that of Salmonella Typhi from blood samples of patients.

Things to Note:

• Speed and Accuracy: It provided the effectiveness of 98-100% accuracy within 3-5 hours of its application.
• Applications: These tests can diagnose typhoid fever early, even if very few bacteria are identified.
• Cost: The high cost hinders access to PCR in resource-scarce settings.

PCR is probably the only diagnostic tool that can confirm typhoid in all four stages, thereby making it one of the most important tools for accurate diagnosis of this disease.

6. Stool and Urine Culture: Exceptional in Certain Cases:

Stool and urine cultures are tests for Salmonella Typhi from faeces or urine samples. They can help screen carriers still shedding the bacteria even after recovery periods.

Take Home Points:

• Accuracy: Stool culture provides only approximately 30 to 40 percent^[5] results, while urine culture will be even below that, about 10 to 20 percent. 
• Time: Samples can go for a prolonged period of up to 48 hours before they can give results.

While not as sensitive or as specific as blood and bone marrow cultures, these tests indicate the course of typhoid fever in recovering patients.

7. Antigen Detecting Article: ELISA test

ELISA is a valuable test for detecting Salmonella Typhi antigens or antibodies in an individual’s blood sample.

Some Fast Points:

• Speedy: ELISA’s turnaround time is rapid: up to 1 to 2 hours. This is a rapid way of testing.
• Accuracy: It gives very high accuracy for diagnosing typhoid fever in areas with endemic diseases. The 4 stages of typhoid fever are diagnosed primarily in the early and mid stages and confirmed through tests.

8. New Diagnostics: Biosensors and Point-of-Care Testing for Everyone

New technologies have provided these portable devices-to-date biosensors and point-of-care testing kits for diagnosing typhoid fever. These are made for resource-poor settings and hold out a robust diagnosis.

Some Facts:

• Advantages: Cost-effective, easily carryable, and turnaround time between 30 and 60 minutes.
• Research: A report in Nature Biomedical Engineering published some biosensors that were over 95 per cent effective in detecting typhoid.

These modern testing methods will play an essential role in diagnosing typhoid insects at all stages of infection and in outreach access areas or developing communities.

Comparing Diagnostic Tests( make an infographic)

Importance of Early Diagnosis in the 4 Stages of Typhoid Fever

Infectious diseases and differences pose major hindrances to practical diagnosis. Moreover, early diagnoses would avoid complications like perforation of the gut, systemic infections, and other acute manifestations resulting from typhoid fever. Early tests and treatment ropes in most (98%) cases recoverable from possible typhoid deaths within the WHO figures.

Conclusion

Typhoid diagnosis is thus taken to include a number of all possible tests, each with benefits and disadvantages. Widal test is the oldest and most traditional way of testing, but even more advanced sophistication by PCR is not lacking in diagnosis. The stage of the disease determines the choice, the presence of equipment, and the patient’s condition. It is rare that with the use of diagnostically applied tests to identify all 4 stages of typhoid fever. Lastly, a deep understanding and knowledge of all the tests can help you identify which stage you are at.