Enteric Fever:- Part 3 – Typhidot Test for Diagnosis of Typhoid fever

Typhidot Test

Sample

• Venous blood is taken to get the serum.

Indication

• The main indication is to diagnose Typhoid fever.

Test principle of Typhidot Test

1. This test detects antibody IgG and IgM in the serum of the patient.
2. The commercial kit manufacturer claims that Typhidot can detect antibodies in the first few days of fever when Widal is negative.
3. The Typhidot is easy to perform and requires no special equipment.
4. Typhidot will be a useful complementary test to blood culture and the Widal test in typhoid fever diagnosis.
5. The widal test is positive after at least 7 to 10 days of Typhoid fever.

Result accuracy of Typhidot 

1. This rapid test accuracy is not clear.
2. The Typhidot test gave a sensitivity of 100 percent and specificity of 80 percent when bacteremic patients were analyzed.
3. Another study shows the test’s sensitivity and specificity using blood culture as the gold standard were 92.3 % and 98.8 %, respectively, for typhoid fever.
4. One study was done in Pakistan.

Interpretation of the Typhidot test result:

Positive line	Interpretation
IgM	Acute typhoid fever
IgM + IgG	Acute typhoid fever
IgG only + IgM (negative)	Past infection

• NOTE: My personal experience is that widal is still a better option and more reliable than Typhidot because Typhidot false-positive results are very common.

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