Step 1: Identify the pathogen behind typhoid.
Typhoid fever is caused by the bacterium Salmonella typhi, picked up from food or water contaminated with the bacteria, and it settles in the gut and bloodstream.
Step 2: Ask what a confirmatory test needs to detect.
Confirming this specific infection needs a test that picks up something unique to Salmonella typhi, not just a generic marker of "some infection is present."
Step 3: See what the Widal test actually measures.
The Widal test mixes the patient's blood serum with known Salmonella O and H antigens and checks for agglutination (clumping). A rising titer of antibodies against these specific antigens confirms the patient's immune system is actively responding to Salmonella typhi.
Step 4: Compare with the other three tests.
ELISA is a general antigen-antibody detection format used for many different diseases, not specific to typhoid on its own. Western blot separates and identifies specific proteins, commonly used for confirming viral infections like HIV, not typhoid. A liver function test only checks how well the liver is working, it says nothing about which pathogen is present.
Step 5: Weigh practicality too.
Widal test is cheap, quick, and widely available, which is why it remains the standard first-line confirmatory test for typhoid in most clinical settings, especially where advanced lab facilities are limited.
Final Answer:
Typhoid is confirmed using the Widal test, option (1).