Microfilaria (filaria) blood test
Quick answer: This test looks for microfilariae, the young worms of filaria (lymphatic filariasis), in blood using a smear or the QBC method. It is ordered for swelling of the legs or scrotum, unexplained fever or high eosinophils in areas where filaria occurs.
- SampleBlood
- TakesAbout 5 minutes, usually at night
- Before the testA night-time blood sample is often needed, as the worms are mostly in the blood at night; follow the lab's timing.
How the test is done
- 1Blood is usually drawn at night, around 10 pm to 2 am
- 2A thick smear is made and stained, or a QBC tube is spun
- 3The lab looks for microfilariae under the microscope
- 4Results are reported as seen or not seen
What your results can mean
Reading your report
A negative result does not rule out filaria, and antigen tests may be added; discuss it with your doctor.
If the result is outside the usual range
Finding microfilariae confirms filarial infection, which can cause swollen limbs, scrotal swelling or milky urine. A negative result does not rule out infection, as the worms may not be in the blood at the time.
Who usually has this test
People with swelling of the legs or scrotum, milky urine, or fever with swollen glands, especially in areas where filaria is common.
Risks and aftercare
Bruising is possible; you can go back to sleep normally after the night sample.
Names and options
Also called: filaria test, MF smear, QBC for MF, night blood smear
Options
- Filarial parasite smear
- Microfilaria smear
- QBC for microfilaria
Listed by the hospital as
- FILARIAL PARASITE SMEAR EXAMINATION
- MICROFILARIA PARASITE, SMEAR EXAMINATION
- QBC FOR MF
Questions about this test
Why is the blood taken at night?
In India, the common filarial worms release microfilariae into the blood mostly at night. A night sample improves the chance of finding them.
Is filaria found in Karnataka?
Lymphatic filariasis is found in some districts of Karnataka and in many other states. India runs mass drug programmes to eliminate it.
Can filaria be treated?
Yes, medicines can kill the microfilariae, and care of swollen limbs reduces problems. Your doctor will advise on treatment.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
Reception
Waiting area
IVF lab
This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.