Typhidot Test
The Typhidot test is a rapid blood test used to detect typhoid fever. It identifies IgM and IgG antibodies against Salmonella typhi, the bacteria responsible for typhoid. It helps in early diagnosis, especially when culture results are pending or unavailable.
The Typhidot test is a serological diagnostic tool designed to detect antibodies (IgM and IgG) in the blood against the outer membrane protein (OMP) of Salmonella typhi – the bacteria that causes typhoid fever. Typhoid is a potentially serious illness commonly spread through contaminated food and water, especially in areas with poor sanitation.
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How the Typhidot Test Works:
IgM antibodies: Appear early in infection and indicate a recent or current infection.
IgG antibodies: Appear later and indicate past exposure or a progressing infection.
The test is performed using a dot enzyme-linked immunosorbent assay (dot-ELISA) technique. A positive result appears as colored dots indicating the presence of specific antibodies.
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Why It’s Done:
Diagnose typhoid fever quickly (within 2–3 days of fever onset)
Useful when blood cultures are negative or delayed
Helps in differentiating current vs. past infections
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Sample Required:
A blood sample from a vein.
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Preparation:
No special fasting or preparation is required.
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Results Timeline:
Results are usually available within 1–2 hours.
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Advantages:
Rapid and simple to perform
Detects infection earlier than Widal test
Helps reduce delays in treatment decisions
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Limitations:
May show false positives in other febrile illnesses
Cannot distinguish between S. typhi and S. paratyphi
Best used alongside clinical symptoms and other tests
The Typhidot test is a valuable screening tool for early detection of typhoid fever, especially in areas where blood culture facilities are limited. However, results should be interpreted in conjunction with clinical findings for an accurate diagnosis.