Haemoglobin and PCV (Hb, haematocrit)
Quick answer: This combined test measures haemoglobin and packed cell volume (haematocrit), the share of blood made up of red cells. It is used to check for anaemia, dehydration or too many red cells.
- SampleBlood
- TakesAbout 5 minutes
- Before the testNo special preparation is usually needed.
How the test is done
- 1Blood is drawn into a purple-top EDTA tube
- 2An analyser measures the haemoglobin
- 3PCV is measured by spinning a small tube or worked out by the analyser
- 4Both results are reported together
What your results can mean
Reading your report
Ranges differ by sex, altitude and in pregnancy; discuss the results with your doctor.
If the result is outside the usual range
Low values can point to anaemia or extra fluid in the blood, and high values to dehydration, smoking or a bone marrow condition. In dengue, a rising PCV can be a warning sign of fluid leaking from blood vessels.
Who usually has this test
People with anaemia, dehydration or dengue, and those being monitored after bleeding.
Risks and aftercare
Bruising is possible; in dengue, keep drinking fluids as your doctor advises.
Names and options
Also called: Hb PCV, Hb and haematocrit
Listed by the hospital as
- HB, PCV
Questions about this test
Why is PCV checked repeatedly in dengue?
A rising PCV with falling platelets can show plasma leaking out of blood vessels. Doctors use the trend to guide fluids.
How are Hb and PCV related?
In many people, the PCV is roughly three times the haemoglobin. A mismatch can give clues about red cell size or a sample problem.
Can dehydration affect the result?
Being dehydrated can make both values look higher. Drink as usual before the test.
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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.
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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.