Enteric fever – Part 4 – Typhidot Test for Diagnosis of Enteric fever
- Venous blood is taken to get the serum.
- The main indication is to diagnose Typhoid fever.
- This test detects antibody IgG and IgM in the serum of the patient.
- The commercial kit manufacturer claims that Typhidot can detect antibodies in the first few days of fever when Widal is negative.
- The Typhidot is easy to perform and requires no special equipment.
- This will be a useful complementary test to blood culture and the Widal test in the diagnosis of typhoid fever.
- Widal test is positive after at least 7 to 10 days of Typhoid fever.
- The Typhidot test gave a sensitivity of 100 percent and specificity of 80 percent when bacteremic patients were analyzed.
- Another study shows the sensitivity and specificity of the test using blood culture as gold standard were 92.3 % and 98.8 % respectively for typhoid fever.
- One study was done in Pakistan.
Interpretation of Result
- IgM line positive = Acute typhoid fever.
- IgM +IgG positive = Acute typhoid fever.
- IgM negative and IgG positive = Past infection
- NOTE: My personal experience is that widal is still a better option and more reliable than Typhidot because false-positive results are very common.