Typhoid Test Report: Typhidot IgM vs IgG and Blood Culture
Which typhoid test you get should depend on which day of fever you’re on. A blood culture drawn in the first week, before any antibiotic, is the test that confirms typhoid; a Typhidot IgM or IgG strip only hints at it. Here’s how to read a typhoid test report line by line, what IgM and IgG mean, and what the culture sensitivity sheet is telling your doctor.
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Which typhoid test on which day of fever
Typhoid tests look for two different things. Some look for the germ itself (culture), while others look for the body’s antibody response (Widal, Typhidot), and because those two things show up at completely different points in the illness, a test that is excellent on day three can be close to useless on day twelve, and the other way round. The germ is easiest to catch early, in the blood. Antibodies take days to build. So the “right” test moves as the fever goes on.
| Day of fever | Most useful test | Why |
|---|---|---|
| Days 1 to 7 | Blood culture | Bacteria are circulating in the blood; antibodies are still low |
| Days 4 to 10 | Typhidot IgM, alongside culture | IgM starts to rise, but results are rough |
| Week 2 onwards | Widal pair, stool culture | Antibodies are up; the germ may appear in stool |
| Fever returning after a course | Culture again | The doctor needs the germ to see what still works |
Day 1 is the first day you felt feverish, not the day you first saw a doctor or the day the family finally agreed it was more than a chill. Write it down. Almost every report makes more sense once the doctor knows the fever day.
Our Widal test report guide explains the 1:80 and 1:160 numbers on their own, so this page doesn’t repeat them.
What is IgM and IgG in a typhoid test?
Typhidot (and similar rapid “ICT” or card tests) look for antibodies to a protein on the outside of the typhoid germ. The card has separate lines for two antibody types.
- IgM is the body’s first, fast response. A positive IgM suggests a recent infection, often from around day 4 or 5 of fever.
- IgG comes later and lasts much longer. A positive IgG can mean a later stage of this illness, or simply that you had typhoid, or met the germ, months or years ago.
So an adult with “IgG positive, IgM negative” who had typhoid three years ago has learned nothing new from this test. It proves nothing about the fever you have now.
Read the card result like this
IgM positive, IgG negative: fits a recent infection, but check with culture. IgM and IgG both positive: could be current or a recent one, the doctor weighs it. IgG only: often old exposure. Both negative on day 3: too early to say much.
Rapid cards are quick and cheap, and they’re better than a single Widal in some settings, but they miss real cases and flag some people who don’t have typhoid. That’s why they support, not replace, culture.
Blood culture: the test that confirms typhoid
A blood culture puts a sample of your blood into a bottle of broth and waits to see whether typhoid bacteria grow. If they do, that’s proof. It also lets the lab test which antibiotics still kill that particular germ.
- Ask for it early, ideally in the first 7 days of fever.
- Get it drawn before the first antibiotic, even a single strip from the chemist; one or two days of antibiotic can stop the germ growing in the bottle.
- Expect a proper blood draw, usually around 10 ml for an adult into a special bottle, and less for a child; the lab sets the volume.
- Wait 2 to 5 days for a result. A “no growth” preliminary report at 48 hours isn’t final.
- Collect the final report with the sensitivity sheet and take it straight back to the doctor.
Culture isn’t perfect either. Small blood volumes and earlier antibiotics make it miss cases. A negative culture with a strong clinical picture doesn’t close the question; the doctor may still treat or test again.
Reading the sensitivity sheet (S, I and R)
If typhoid grows, the lab tests it against a panel of antibiotics and prints a letter beside each one:
- S (sensitive): that drug stopped the germ in the lab.
- I (intermediate): borderline.
- R (resistant): the germ survived it.
Since 2016, Pakistan has had an extensively drug-resistant (XDR) typhoid strain, first seen in Sindh, that resists most older antibiotics. A sheet with many R letters is the reason your doctor may switch the plan after a few days, or refer you to hospital. That isn’t the doctor getting it wrong. It’s the report doing its job, telling everyone which weapons still work against the particular germ growing in your bottle rather than the one in last year’s textbook. Never match the letters to a medicine yourself.
Stool culture and other typhoid tests
Later in the illness, from the second week, typhoid germs may show in stool. Stool culture is also used to check whether someone who has recovered still carries the germ, which matters for cooks and food handlers. Bone marrow culture is the most sensitive test of all but is a hospital procedure used only when doctors need it. Urine culture has a small role. You won’t normally need to ask for any of these yourself; your doctor chooses which one fits the week of illness, your symptoms and what the earlier reports showed.
Go to a doctor the same day for fever past 3 days or 39 °C and above with severe or worsening belly pain, a hard or swollen tummy, confusion or unusual sleepiness, black or bloody stools, repeated vomiting, or no urine for 6 hours. Also the same day for any fever in a child under 5 or a baby under 3 months, fever in pregnancy, and fever returning after you’ve finished an antibiotic course. Never start, stop or change an antibiotic on your own because of a typhoid test report.
What commonly confuses typhoid test results
- An antibiotic bought on day two. This is the big one. It can make culture negative and muddle antibody tests.
- The typhoid vaccine. It can leave antibodies that show on Widal and some rapid tests.
- Past typhoid. IgG and H titres may stay up for years.
- A different fever. Dengue, malaria and others can cross-react on antibody tests; see our dengue, chikungunya and typhoid symptom table.
- Testing too early. Antibody tests on day 1 to 3 are often negative.
The antibiotic you bought on day two is the reason your culture may come back empty.
Myth: “IgG positive means I have typhoid right now”
People read “positive” and stop there. But IgG is the long memory. An adult in a typhoid-prone city often carries IgG from years ago, and a card that shows only IgG says almost nothing about this fever. The same goes for “typhoid ki report positive aayi, teesri baar typhoid ho gaya”. Repeated “typhoid” diagnoses based on antibody tests alone are often the same old antibodies being read again.
The flip side: a truly positive culture is serious, and fever that returns after a finished course needs a doctor quickly, not another strip from the pharmacy.
Questions to ask your doctor about your typhoid test
- Was my blood sample taken before I had any antibiotic?
- Is this result IgM, IgG or both?
- Should we send a blood culture, and when will the sensitivity report be ready?
- If the culture shows resistance, how will that change the plan?
- Do I need a stool culture later, especially since I cook for the family?
- Should dengue or malaria be tested too?
After typhoid, appetite and weight take time. Our guide to regaining weight after typhoid or dengue picks up from there. More plain-English report guides live under Desi Remedies.
Typhoid test report: common questions
What is the best test to confirm typhoid?
Blood culture. It finds the germ itself and shows which antibiotics still work against it. It works best in the first week of fever and before any antibiotic is taken.
What is IgG and IgM in a typhoid test?
They are two antibody types. IgM appears first and suggests a recent infection. IgG appears later and can last for years, so IgG alone often reflects past exposure rather than the current fever.
What does Typhidot IgG positive and IgM negative mean?
It usually points to past contact with typhoid rather than a new infection, especially in an adult who has had typhoid before. It doesn’t prove or disprove the current illness. Your doctor may ask for a culture.
Typhoid test report kaise dekhe?
Find the test name first: Widal, Typhidot, or culture. For a card test, read the IgM and IgG lines separately. For a culture, look for “growth” or “no growth”, and if typhoid grew, the S, I and R letters on the sensitivity sheet.
What is the typhoid test normal range?
For card tests the normal result is “negative” for both IgM and IgG. For culture it is “no growth”. Widal uses dilutions, where many labs treat below 1:80 as not significant. Your lab’s printed range wins.
How long does a typhoid blood culture take?
Usually 2 to 5 days for a positive result with sensitivity, and up to about a week before a lab calls it final “no growth”. Rapid cards give an answer in about 15 to 30 minutes, but they are far less definite.
Can I get a typhoid test after starting antibiotics?
You can, but culture becomes less likely to grow the germ, and antibody tests can be blunted. Tell the lab and the doctor exactly what you took and when. Never stop a prescribed course to “get a cleaner test”.
What is XDR typhoid?
Extensively drug-resistant typhoid, a strain that has spread in Pakistan since 2016 and resists most older antibiotics. It is found through blood culture sensitivity testing, which is one more reason to get a culture before treatment starts.
Is Typhidot better than Widal?
It is quicker and separates recent (IgM) from older (IgG) antibodies, which a single Widal can’t. But both are antibody tests with false positives and misses. Neither beats a blood culture for confirming typhoid.
Why did my fever come back after the typhoid course?
It can mean a relapse, a resistant germ, a complication or a different illness. It needs a doctor the same day, and often a repeat culture. Don’t restart leftover tablets on your own.
Can children have a blood culture?
Yes. Labs take a smaller volume suited to the child’s size. It’s the same reliable test, and it matters just as much for children because resistant typhoid affects them too.
Does a negative typhoid test mean I don’t have typhoid?
Not always. An early antibody test, or a culture taken after antibiotics, can miss real typhoid. If fever continues past 3 days, tell your doctor even with a negative report.