Microfilaria Detection (Knott's Method)
Knott's test looks for microfilariae, the tiny baby worms of heartworm and other filarial worms, in a blood sample under the microscope. It can help find infection in dogs and cats.
- Sample
- Whole blood (EDTA)
- Quantity
- 3 mL
- Report
- Same day to 24 hours
- Collection
- Free in Bhopal
What this test checks
- Microfilariae (larvae of filarial worms) in the blood
- Whether larvae are present or absent in the sample
- Size and shape of larvae, which can help tell worm types apart
Benefits of this test
- Finds baby worms that a routine blood smear can miss.
- Can help show infection with heartworm or other filarial worms.
- Helps tell some worm types apart by the size and shape of the larvae.
- Needs only a small blood sample.
- Helps your vet decide whether other heartworm tests are needed.
When your vet may advise it
- A dog that coughs, tires easily or breathes with effort, with no clear cause.
- Skin lumps, itching or sores in a dog from an area with many mosquitoes.
- A dog or cat that has never been checked for blood worms and lives where mosquitoes are common.
- A positive result on a heartworm antigen kit, to look for larvae in the blood.
- Unexplained weakness or weight loss in an animal that lives where mosquitoes are common.
About this test
Some worms, such as heartworm, live as adults in the heart, blood vessels or under the skin. Mosquitoes carry them from one animal to another. The adult female worms release tiny larvae called microfilariae into the blood. Knott's method is a way of finding these larvae, which are too small to see by eye.
A measured amount of blood is mixed with a solution that bursts the red blood cells. The mixture is spun in a machine so that the heavier larvae settle at the bottom. The settled material is stained and examined under the microscope. This concentrating step finds a small number of larvae better than a simple blood smear can. The size and shape of the larvae can help tell types of worm apart.
A negative result does not fully rule out heartworm, because some infected animals have no microfilariae in the blood. Vets may use other tests together with it.
How to prepare
No fasting is needed; follow your vet's advice. Blood is collected into an EDTA tube (a tube with a chemical that stops clotting) and gently mixed. Collection is free anywhere in Bhopal; from outside Bhopal, the blood sample can be sent by courier, bus parcel or through your vet after you speak to the lab.
Reading the result
Seeing microfilariae shows that larvae were present in the blood sample, while a negative result does not fully rule out adult worms. A registered veterinarian reads it with your pet's signs, history and other tests and decides what to do next.
Questions about Microfilaria Detection (Knott's Method)
What are microfilariae?
Does a negative Knott's test rule out heartworm?
What does a positive Knott's test mean?
Can cats be tested with Knott's method?
Before you book this test
Why this notice: so you know, before you book, how a test is done, what its limits are and who is responsible.
- Where it is tested. Some tests are done wholly or partly by an independent partner laboratory. The lab tells you before booking if this test is sent out, and the report names the laboratory that did it.
- What a result can and cannot tell you. No test is right every time. A normal result does not rule out every disease, and an abnormal result does not prove one. A registered veterinarian should read the report with the animal’s signs and history before any treatment is started, changed or stopped.
- The sample. A sample that is clotted, too small, wrongly labelled, leaking or too old may be rejected or reported with a note, and the lab may ask for a fresh one.
- Reporting time. Same day to 24 hours. Times are estimates, not guarantees, and the lab confirms the time when you book.
- Emergencies. A booking or a pending report must not delay urgent care. If an animal has collapsed, struggles to breathe, has fits or bleeds heavily, call a veterinarian at once.
Please read our Terms of Service, Medical Disclaimer, Privacy Policy and Refund and Cancellation Policy. Pashupatinath Vet Lab is operated by Duaji Healthcare and Tech Private Limited. This page is general information and does not replace a veterinarian’s advice.
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Microfilaria Detection (Knott's Method): Bhopal and the big cities of Madhya Pradesh
Free sample collection anywhere in Bhopal. From the other cities, send the sample by courier, bus parcel or through your local veterinarian, and the report comes to you online.
Free collection in these Bhopal areas
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Heartworm Tests in Dogs and Cats
Heartworm is checked with antigen kits that find proteins from adult female worms, and with microscope or RT-PCR tests for the tiny young worms in blood. Cats are tested differently from dogs.
18 Oct 2026