Health guides
Fever in the Tricity: which test, and when
Every September, our collection counter fills up with the same conversation. Someone has had fever for two days, a relative has told them it is dengue, and they want the test done today.
Often, today is the wrong day.
The short version
- The day of your fever decides the test. NS1 early, IgM from about day 5. Testing on the wrong day can read negative when you do have dengue.
- Paracetamol only until dengue is ruled out — not ibuprofen, aspirin or Combiflam.
- Watch how you feel, not the platelet number. The most dangerous phase often begins as the fever settles.
The single most common mistake in fever testing is not choosing the wrong test. It is doing the right test at the wrong time, getting a negative result, and going home reassured. This article is about timing.
Before anything else — two things that matter more than any test
- For fever and body ache, take paracetamol only. Until dengue has been ruled out, avoid aspirin, ibuprofen, nimesulide, diclofenac and combination painkillers such as Combiflam. They increase the risk of bleeding, which is the main danger in dengue.
- Do not wait for a test result if you are getting worse. The warning signs further down this page mean going to a hospital the same day, whatever any report said.
Why the day of your fever matters
Dengue is diagnosed by two completely different kinds of test, and each one only works during a particular window.
| Test | What it detects | When it works |
|---|---|---|
| NS1 antigen | A protein released by the virus itself | From day 1, most reliable in the first 5 days, and often still positive to about day 7 |
| IgM antibody | Your immune system's response to the virus | From about day 5 onwards |
| IgG antibody | Past or repeat infection | Interpreted alongside IgM |
Swipe the table sideways to see all columns.
Which test works on which day
NS1 fades as antibodies appear. The narrow band between them is where a single test can read negative even in real dengue.
Count day 1 as the first day you had fever, not the day you decided to get tested.
The overlap is where mistakes happen. NS1 begins to fall away around the time IgM starts to appear, so a test done around day 4 or 5 can occasionally catch the tail of one and the beginning of the other and read negative on both while you genuinely have dengue. It is not the rule, but it is common enough that a single negative test in the first few days should never be treated as the end of the matter.
What this means in practice:
| Day of fever | What to do |
|---|---|
| Day 1–2 | NS1 antigen, with a complete blood count |
| Day 3–5 | NS1 antigen, and IgM alongside it — it costs no extra visit and catches an early converter |
| Day 5 onwards | IgM antibody, with a complete blood count |
| Negative early, fever continues | Repeat after day 5. A negative early test does not rule out dengue — but do not wait for that repeat if you feel worse. |
Swipe the table sideways to see all columns.
We report dengue NS1 and antibodies by ELISA rather than by rapid card. Rapid cards are quicker and cheaper; they are also less reliable, and the national programme does not recommend them for diagnosis. If you tell us which day of fever you are on, we will tell you which test to do.
Some people should not wait and watch
- Babies and young children. Any fever in a baby under three months, or a child who will not feed, has passed no urine for six to eight hours, has cold hands and feet, or is drowsy or unusually irritable — go now. Children deteriorate in hours, not days.
- Pregnancy. Fever in pregnancy should be assessed by your obstetrician the same day, not managed at home.
- Older adults and anyone with diabetes, kidney, liver or heart disease. The usual warning signs can appear late or not at all.
- Anyone on blood thinners — warfarin, clopidogrel, apixaban and similar — or on regular anti-inflammatory painkillers. Tell your doctor early; bleeding risk is different for you.
It is not always dengue
September and October in the Tricity bring several illnesses that look identical in the first three days. Fever, body ache, headache. The differences show up in the tests, not in how you feel.
| Illness | Test | Notes |
|---|---|---|
| Dengue | NS1 / IgM, by day of fever | Low platelets, low white cells |
| Chikungunya | IgM from about day 5 | Severe joint pain that can persist for weeks |
| Malaria | Peripheral smear and rapid antigen | Still worth testing despite falling numbers |
| Typhoid | Blood culture — see below | The test most often done badly |
| Scrub typhus | IgM ELISA | Under-tested in North India. IgM is often still negative in the first week, so a negative test early does not clear it. Look for an eschar — a small black scab, often in a skin fold — decisive when present, but found in a minority of patients here. |
| Influenza | Rapid antigen or PCR | Cough and sore throat more prominent |
Swipe the table sideways to see all columns.
A complete blood count is worth doing on day one regardless of which illness is suspected. The pattern of white cells and platelets narrows the field faster than any single antibody test, and it gives us a baseline to compare against later.
Typhoid, and the trouble with antibody tests
If typhoid is suspected, blood culture is the test that answers the question. It grows the organism itself, which both confirms the diagnosis and shows which antibiotic will work. It takes longer and it costs more.
The antibody-based alternatives — the Widal test, and rapid cards such as Typhidot — are quicker and cheaper, and they are much weaker evidence than most people assume. They can read positive in someone who had typhoid years ago, in someone vaccinated against it, and in someone who has an entirely different infection; during dengue season in particular, a meaningful share of dengue patients test falsely positive on a typhoid antibody card. They can also read negative in genuine early typhoid.
That does not make them useless, but it does mean a positive antibody result is a reason to look further, not a diagnosis to start treatment on. If you are having a fever panel done, ask us what each test in it can and cannot tell you.
One piece of timing that matters more than which test you choose: blood culture should be collected before antibiotics are started. Once treatment has begun the organism often will not grow, and the opportunity is gone. If typhoid is a possibility, ask about culture on day one rather than day five.
Platelets: what the number actually means
More anxiety is generated by platelet counts in this city than by almost anything else we report. Some of it is warranted. Most of it is not.
What is normal: 150,000 to 450,000 per microlitre.
What happens in dengue: platelets fall, typically reaching their lowest point around day 4 to 7 — often just as the fever is settling and you are starting to feel better. This is expected. It is not, by itself, an emergency.
When it actually matters: doctors act on bleeding and on clinical condition, not on the number alone. Transfusion is generally reserved for counts far below what most families assume, or for active bleeding. A falling count in someone who is otherwise well, drinking fluids and passing urine normally is monitored, not treated.
What a platelet count usually does
The lowest point tends to arrive as the fever settles — which is exactly when people assume the worst is over.
How often to check
This depends entirely on where you are in the illness, and it is the one place where a single rule does harm:
- Well, at home, in the first few days: a count every 24 to 48 hours is usually enough. Testing more often than that mostly generates anxiety.
- Once the count is falling, or once the fever starts to settle: this is the critical phase, and your doctor may want it checked far more often — as frequently as every 6 to 8 hours. Follow the interval your doctor gives you, not this page.
Papaya leaf extract. Small trials suggest platelet counts may rise somewhat faster with it, but there is no reliable evidence that it prevents bleeding or changes how the illness ends, and the trials are small and poorly controlled. Home-made preparations have no standard dose, and there are published reports of liver and kidney injury. Tell your doctor if you are taking it. It is not a substitute for fluids, rest and monitoring.
Warning signs — go to a hospital
Test results are not the thing to watch. These are. If any of them appear, go to a hospital rather than waiting for a report:
- Severe or worsening abdominal pain
- Persistent vomiting, or inability to keep fluids down
- Bleeding — from the gums or nose, or blood in vomit or stool
- Unusual drowsiness, restlessness or confusion
- Cold, clammy skin
- Passing much less urine than usual
- Sudden collapse or breathlessness, particularly as the fever falls
The most dangerous phase of dengue often begins as the temperature comes down. Feeling better is not the same as being better.
How to prepare
- No fasting is needed for any of the fever tests above. Come whenever you can.
- Bring the date your fever started. It determines which test we do.
- Bring any previous reports. A falling platelet count means something a single reading does not.
- Tell us about antibiotics. If you have already started them, blood culture becomes much less reliable, and we need to know.
- Tell us what you are taking for the fever, including any painkillers and any home remedies.
Home collection
We collect from Chandigarh, Panchkula, Mohali, Zirakpur, Kharar and New Chandigarh. During fever season a home collection is often the sensible choice — for the patient, and for everyone else in the waiting room.
Message us on WhatsApp with the patient's area and the day of fever, and we will confirm a slot and tell you which test is appropriate.
Frequently asked questions
I have had fever for two days. Which test should I do?
My dengue test was negative but I still have fever. What now?
How often should platelets be checked?
Is the Widal test enough for typhoid?
What can I take for the fever?
Do I need to fast?
Does papaya leaf extract raise platelets?
Can you collect from my home?
Tell us your day of fever and we will tell you which test is appropriate — and whether it is worth doing today or waiting.
Ask on WhatsAppMalhotra Labs has been reporting for patients and physicians in Chandigarh since 1996. Every report is reviewed and signed by an MD pathologist, not released automatically by an analyser.