Typhi Dot - IgG : Salmonella typhi – ES154
🩸 Typhoid Fever TestReport: Same Day
Sample Type: Blood (Serum)
Test Code: ES154
The Typhi Dot - IgG test is a rapid serological test that detects the presence of IgG antibodies in the blood against Salmonella typhi, the bacterium responsible for Typhoid fever (also known as enteric fever). IgG antibodies are part of the body's long-term immune memory.
✔ Helps in diagnosing a recent or past infection with Salmonella typhi.
✔ Can indicate a relapse, reinfection, or an immune response in a chronic carrier.
✔ Often performed alongside the Typhi Dot IgM test for a more complete picture of the infection timeline.
✔ Simple blood test with same-day reporting.
Understanding Typhoid Antibodies: The Role of IgG
When your body is infected with a bacterium like Salmonella typhi, your immune system mounts a defense by producing proteins called antibodies. There are different types of antibodies that appear at different stages of an infection. The Typhi Dot test looks for two specific types: IgM and IgG.
This test specifically measures IgG (Immunoglobulin G) antibodies. IgG is the most abundant type of antibody and is a crucial part of your body's long-term immune defense. Unlike IgM antibodies, which appear early in an infection and then fade, IgG antibodies take longer to develop (typically after 10-14 days of illness) but can then persist in the blood for months, years, or even a lifetime, providing long-term immunity.
What Does a Positive Typhi Dot IgG Result Mean?
A positive result for Typhi Dot IgG means that your immune system has produced long-term memory antibodies against the typhoid bacterium. This can be interpreted in several ways, and a doctor's evaluation is essential:
- Past Infection: You may have had typhoid fever in the past, and your body has retained the immune memory. You are not currently sick, but the antibodies are still present.
- Recent or Late-Stage Infection: If you are currently feeling unwell or are in the recovery phase of a prolonged fever, a positive IgG result (especially if IgM is negative) can indicate that you are in the later stages of a typhoid infection.
- Reinfection or Relapse: In someone who has had typhoid before, a new infection can sometimes cause a rapid and strong IgG response.
- Chronic Carrier State: A small percentage of people who get typhoid can become chronic carriers, meaning they continue to harbor the bacteria without symptoms. A persistent IgG level may be seen in these individuals.
Because IgG indicates a memory response, it is generally not the primary test used to diagnose an acute, early-stage typhoid fever. For that, the Typhi Dot IgM test or a blood culture is preferred. The IgG test provides valuable information about the infection's timeline and a person's immune history with the disease.
Frequently Asked Questions (FAQ)
IgM antibodies are the first to appear during an active, new infection (usually within a week) and then decline. IgG antibodies appear later in the infection (after 10-14 days) and can remain in the blood for a very long time, indicating past exposure or long-term immunity.
Not necessarily. A positive IgG result on its own often indicates a past infection. Your doctor will interpret this result based on your current symptoms, clinical history, and possibly the result of an IgM test to determine if you have an active infection.
A blood culture, which tries to grow the bacteria from a blood sample, is considered the "gold standard" for diagnosing an active typhoid infection, especially in the first week. However, the Typhi Dot test is much faster (same-day report) and can still be useful, particularly after the first week of fever when bacteria may be harder to find in the blood.
No, fasting is not required for the Typhi Dot - IgG test.
Your report will be available on the same day for samples submitted by 4:30 PM. You will typically receive it online via email or WhatsApp.