Health Library / Seasonal & local
Dengue test in Lucknow: when to test, which test, and what the platelet count really means
· 7 min read · Lucknow
Every monsoon in Lucknow the same conversation repeats in thousands of households: someone has a high fever, a neighbour says get the platelets checked, and nobody is sure whether it is too early to test or already too late. The timing genuinely matters, because the dengue tests do not all look for the same thing.
This is a guide to which test is right on which day of fever, what the platelet count is actually being watched for, and — the part that matters most — the warning signs that mean stop reading and go to a hospital.
NS1, IgM, IgG: three tests, three different days
NS1 antigen detects a protein the virus itself sheds, and it is the early test. It is most reliable from the first day of fever to about the fifth. Test too late and NS1 can be negative even in someone who genuinely has dengue.
IgM antibody is the opposite. Your body takes a few days to make it, so IgM usually becomes detectable from around day five. A negative IgM on day two means very little; the same test on day six means a great deal more.
IgG appears later still and stays for a long time afterwards. On its own it often reflects a past infection rather than the current fever, which is why it is read alongside the others rather than by itself.
- Day 1 to day 5 of fever — NS1 antigen is the test that will find it
- Day 5 onward — IgM antibody becomes the more useful test
- Both together where the day of fever is uncertain, which is common
- A CBC alongside, because the platelet and haematocrit trend is what gets monitored
Why the platelet count is repeated, not read once
A single platelet value tells you where someone is; the trend tells you where they are going. That is why a doctor managing dengue asks for the CBC to be repeated daily, sometimes twice daily, through the critical phase.
The number people fix on is not the whole story either. Falling platelets matter, but so does a rising haematocrit — a sign that fluid is leaking out of the blood vessels, which is the real danger in severe dengue. The two are read together, which is one reason to have them done at the same laboratory each day, so the results are comparable rather than collected from three different places on three different machines.
Most dengue is managed at home with fluids, rest and paracetamol, under a doctor who is watching that trend. Avoid ibuprofen, aspirin and other NSAIDs unless your doctor has specifically told you otherwise — they affect platelets and bleeding risk.
The signs that mean hospital, now
Dengue has a phase, usually as the fever settles around day four to six, where a patient can appear to be improving while actually deteriorating. These are the warning signs that need urgent medical attention rather than another test.
- Severe or persistent abdominal pain
- Repeated vomiting, or inability to keep fluids down
- Bleeding — gums, nose, in vomit or stool, or unusual bruising
- Extreme lethargy, restlessness, or confusion
- Cold, clammy skin, or reduced urine over several hours
- Any breathing difficulty
Getting tested in Lucknow without adding a trip
Someone with a high fever should not be sitting in a queue. Home sample collection exists precisely for this: a phlebotomist comes to you, the sample is barcoded in front of you, and the report reaches you online — which for a daily repeat CBC over four or five days is the difference between manageable and exhausting.
At Charak, pathology, imaging and cardiac testing sit in one building at Chowk, and the laboratory is NABL-accredited against ISO 15189:2022. For a test whose whole value is in comparing today's number with yesterday's, running them all in one accredited laboratory is not a detail.
This article is general health information, not a diagnosis or a treatment plan. Test results are read alongside your symptoms and history — please discuss yours with your doctor. See our disclaimer.
