What does low MCV mean in a blood test?

Your red cells are smaller than usual. In India this is most often iron deficiency or thalassaemia trait. A ferritin test tells them apart: low ferritin means iron deficiency. If ferritin is normal and your RBC count is high, ask about a test for thalassaemia trait before taking iron.

Is a platelet count of 1.2 lakh dangerous?

Usually not. Without fever or bleeding it is often a temporary dip or clumping in the tube, and a repeat test a few weeks later is the next step. During a fever, especially in dengue season, the doctor will repeat it to see which way it is moving.

Why are my eosinophils high?

Most often allergies, asthma, eczema or intestinal worms, all common in India. A count slightly above the range with known allergies is usually nothing to worry about. A count above 1,500 per cumm, or one that stays high with symptoms, needs a doctor to look for the cause.

My lymphocytes are high and neutrophils are low. What does that mean?

Usually a viral infection, including a recent viral fever. Look at the absolute counts: often the lymphocytes are normal in number and only look high as a percentage because the neutrophils have dipped. A repeat CBC in two to four weeks usually shows both back to normal.

Do I need to fast for a CBC?

No. A CBC can be taken at any time of day. If other tests on the same sample need fasting, such as blood sugar or a lipid profile, fast for those.

Your blood count, value by value.

A CBC (complete blood count, also called a haemogram) counts your red cells, white cells and platelets and measures their size. Here is what each line means, and how to tell a harmless flag from one that needs a doctor.

Reviewed by Dr. Prabhat Arya, MBBS, MD (Internal Medicine)

Reviewed 18 October 2026 · Next review 18 October 2027 · Sources: NHS, MedlinePlus, Testing.com

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Read this first.

Go by the range printed on your own report. Each lab sets its own range for its machine, and the ranges here are typical adult ranges only.

One value just outside the range, with everything else normal and no symptoms, is rarely a problem. Ranges are set so that about 1 in 20 healthy people falls just outside each one.

The lines that matter most are haemoglobin, the total white count (TLC) and platelets. The smaller lines (MCV, MCH, RDW and the rest) mostly help explain why one of those three is off.

In the white-cell breakdown (DLC), look at the absolute count (cells per cumm) if your lab prints it, not only the percentage. A high percentage of one type often just means another type is low. And compare with your last CBC: a steady value matters less than one that is changing.

Haemoglobin (Hb)

The red protein in red cells that carries oxygen

Typical adult range Men 13–17 g/dL; women 12–15 g/dL

High usually means: Usually thicker blood from dehydration, smoking, or living at a height. Less often long-term lung disease, untreated sleep apnoea, or testosterone injections. Rarely the bone marrow making too many red cells.
Low usually means: Anaemia. In India the most common cause is low iron (especially in women with periods or after pregnancy), then low vitamin B12 or folate, blood loss, worms, kidney disease, and inherited conditions such as thalassaemia.
Usually nothing to worry about when: It is slightly low (say 11–12 in a woman) and your MCV and ferritin show mild iron deficiency with an obvious cause such as heavy periods: this needs treating, but not urgently. Slightly high after a day of little water is common.
See a doctor when: It is below 10 g/dL: see a doctor this week. Below 8, or falling quickly from your last report: within a day or two. Any anaemia in a man or a woman whose periods have stopped needs the cause found, even if it is mild: see a doctor within two weeks. High on two reports without smoking or dehydration to explain it: at your next check-up, within a few weeks.

RBC count

Total red blood cell count: how many red cells in each microlitre

Typical adult range Men 4.5–5.5 million/cumm; women 3.8–4.8 million/cumm

High usually means: The same causes as a high haemoglobin. A high RBC count with a low MCV and a normal or only slightly low haemoglobin is a classic sign of thalassaemia trait, which is common in India.
Low usually means: Usually goes with anaemia; read it together with haemoglobin and MCV.
Usually nothing to worry about when: It is slightly off and your haemoglobin is normal.
See a doctor when: It is high with small cells (low MCV): ask your doctor at your next visit about an Hb electrophoresis or HPLC test for thalassaemia trait, and before any pregnancy is planned.

PCV / Haematocrit (HCT)

Packed cell volume: the share of your blood made up of red cells

Typical adult range Men 40–50%; women 36–46%

High usually means: Most often dehydration. In dengue, a PCV that climbs day by day (often by a fifth or more) while platelets fall means fluid is leaking out of the blood vessels; this is a warning sign.
Low usually means: Anaemia; it moves with haemoglobin.
Usually nothing to worry about when: It moves in step with your haemoglobin and that is normal or only mildly off.
See a doctor when: You have dengue or fever and the PCV is rising on repeat tests: see a doctor the same day.

MCV

Mean corpuscular volume: the average size of your red cells

Typical adult range 80–100 fL

High usually means: Large red cells: most often low vitamin B12 or folate (common in vegetarians), regular alcohol, an underactive thyroid, liver disease, or medicines such as methotrexate and some HIV and epilepsy medicines. A mildly high MCV is also seen in pregnancy and in some healthy people.
Low usually means: Small red cells: usually iron deficiency or thalassaemia trait. Long-term inflammation can lower it slightly too.
Usually nothing to worry about when: It is 1–3 fL outside the range, your haemoglobin is normal, and it has been the same for years.
See a doctor when: It is low with low haemoglobin (check ferritin, see iron studies), or above about 105 fL: get B12, folate and thyroid checked within a few weeks (see vitamin B12 and folate).

MCH

Mean corpuscular haemoglobin: how much haemoglobin is in each red cell

Typical adult range 27–32 pg

High usually means: Goes with large cells (high MCV): usually low B12 or folate.
Low usually means: Goes with small, pale cells (low MCV): usually iron deficiency or thalassaemia trait.
Usually nothing to worry about when: It is off alone while MCV and haemoglobin are normal. MCH almost always follows MCV and adds little on its own.
See a doctor when: It is off together with MCV and haemoglobin: read it with those lines above.

MCHC

Mean corpuscular haemoglobin concentration: how packed with haemoglobin the red cells are

Typical adult range 32–36 g/dL

High usually means: Often a sample effect (fatty blood after a meal, cold-reacting antibodies, or red cells breaking open in the tube). True high MCHC is seen in hereditary spherocytosis, an inherited condition with round, fragile red cells.
Low usually means: Pale red cells: usually iron deficiency.
Usually nothing to worry about when: It is just outside the range and everything else is normal. Labs often repeat a high MCHC on a fresh sample.
See a doctor when: It stays high on a repeat test with anaemia, jaundice or gallstones at a young age: see a doctor within a few weeks.

RDW (RDW-CV)

Red cell distribution width: how much your red cells vary in size

Typical adult range 11.5–14.5%

High usually means: A mix of sizes. Common in early iron deficiency (often before haemoglobin falls), B12 or folate deficiency, after bleeding, or while you are recovering on iron or B12 treatment. Low MCV with high RDW points more towards iron deficiency; low MCV with a normal RDW points more towards thalassaemia trait.
Usually nothing to worry about when: It is slightly high and everything else is normal, or you have recently started iron or B12.
See a doctor when: It is high with low or high MCV, or with low haemoglobin: get ferritin or B12 checked at your next visit.

TLC (total leucocyte count, WBC)

Total white blood cells: the cells that fight infection

Typical adult range 4,000–11,000 /cumm (some labs print 4.0–11.0 ×10³/µL)

High usually means: Usually an infection (often bacterial), or the body reacting to stress, an injury, surgery, smoking, pregnancy, or steroid medicines such as prednisolone or dexamethasone. Rarely a blood condition, which is usually obvious from very high counts or abnormal cells on the smear.
Low usually means: Often a viral illness: dengue and other viral fevers commonly bring the count down for a week or two. Typhoid, though bacterial, often does the same. Also some medicines (for example carbimazole for the thyroid, and some antibiotics), low B12, and autoimmune conditions.
Usually nothing to worry about when: It is 11,000–13,000 during or just after an infection, or 3,000–4,000 during or just after a viral fever, and comes back to normal on a repeat test a few weeks later.
See a doctor when: It is above 20,000, or below 3,000 without a recent viral fever: see a doctor this week. It stays outside the range on two tests a few weeks apart: at your next check-up. With fever and a count below 2,000: see the red box below.

Neutrophils (polymorphs)

The main white cells against bacteria; usually the largest share of the DLC

Typical adult range 40–75% (about 2,000–7,500 /cumm)

High usually means: Bacterial infection (for example a urine or chest infection), steroid medicines, smoking, stress, hard exercise, and pregnancy.
Low usually means: Viral infections, typhoid, some medicines (carbimazole and some antibiotics among them), and low B12 or folate. Some healthy people of African, Middle Eastern and South Asian background naturally run a little low.
Usually nothing to worry about when: The percentage is off but the absolute count is normal, or a mild high comes with an infection you know about.
See a doctor when: The absolute count is below 1,000 /cumm: see a doctor the same day if you have fever, otherwise within a few days. Below 1,500 on two tests: at your next check-up. If you take carbimazole and get a fever or sore throat, stop it and get a CBC the same day.

Lymphocytes

White cells against viruses; they also make antibodies

Typical adult range 20–40% (about 1,000–4,000 /cumm)

High usually means: Viral infections, including the tail end of a viral fever, and TB. A high percentage with a normal absolute count is usually because neutrophils are low, not because lymphocytes are high.
Low usually means: Any acute illness or stress, steroid medicines, and some viral infections. A persistently low count may need a check for immune problems, including HIV.
Usually nothing to worry about when: The percentage is high while the absolute count is normal, or it is up during or soon after a viral illness.
See a doctor when: The absolute count stays above 5,000 /cumm on a repeat test a few weeks later, especially in someone over 50: see a doctor within a few weeks so a blood smear can be looked at. Persistently below 1,000 with repeated infections: within a few weeks.

Eosinophils

White cells involved in allergy and in fighting worms

Typical adult range 1–6% (up to about 500 /cumm)

High usually means: Very common in India. Usually allergies, asthma, eczema or allergic rhinitis, or intestinal worms. Some medicines cause it. A high count with a long night-time cough or wheeze can be tropical pulmonary eosinophilia, which is treatable.
Usually nothing to worry about when: It is 6–10% (a few hundred above the range) and you have known allergies, asthma or eczema.
See a doctor when: The absolute count is above 1,500 /cumm, or it stays high with cough, wheeze, rash, tummy upset or weight loss: see a doctor within a few weeks for a stool test and a check of the cause.

Monocytes

White cells that clean up after infection

Typical adult range 2–10% (about 200–1,000 /cumm)

High usually means: Recovery from an infection, long-standing infections such as TB, and inflammatory conditions.
Usually nothing to worry about when: It is mildly high after a recent infection and the rest of the count is normal.
See a doctor when: It stays above 1,000 /cumm on a repeat test a few weeks later, or comes with fever, weight loss or night sweats: see a doctor within a week or two.

Basophils

The smallest group of white cells, involved in allergy

Typical adult range 0–1% (some labs up to 2%)

High usually means: Usually a small machine variation or allergy. Rarely, a persistent rise goes with a bone marrow condition, and then other lines are also off.
Usually nothing to worry about when: It is 1–2% and the rest of the count is normal.
See a doctor when: It stays high together with a high TLC or high platelets on a repeat test: see a doctor within a few weeks.

Platelet count

Small cells that plug bleeding and help blood clot

Typical adult range 1.5–4.5 lakh/cumm (150,000–450,000)

High usually means: Usually a reaction: iron deficiency, recent bleeding, an infection, inflammation, or after surgery. Rarely the marrow making too many.
Low usually means: In India, during a fever, dengue is the first thing to think of; malaria, typhoid and other viral fevers also lower it. Other causes: low B12 or folate, alcohol, liver disease, some medicines, and immune conditions. A falsely low count is common when platelets clump in the tube: a repeat in a citrate tube gives the true count.
Usually nothing to worry about when: It is between 1 and 1.5 lakh with no bleeding and no fever, or 4.5–5 lakh after an infection or with low iron. Repeat it in a few weeks.
See a doctor when: It is below 1 lakh with a fever: see a doctor within a day. Below 1 lakh without a fever: see a doctor this week. Below 50,000: see a doctor the same day. Above 6 lakh on two tests, or above 10 lakh once: see a doctor within a week or two. In dengue, the warning signs in the red box matter more than the number alone.

MPV

Mean platelet volume: the average size of your platelets

Typical adult range 7.5–11.5 fL (varies a lot between machines)

High usually means: Young, large platelets. When platelets are low, a high MPV often means the marrow is working hard to replace platelets used up in the blood, as in recovery from dengue or immune causes.
Low usually means: Small platelets; with a low count it can mean the marrow is making fewer.
Usually nothing to worry about when: It is off and your platelet count is normal. On its own, MPV means very little.
See a doctor when: Only when your platelet count is also off: read it with the platelet line above.

Results that go together.

PatternsTypical, not certain

When you see	It usually means
Low Hb, low MCV, high RDW	Usually iron deficiency. Confirm with ferritin (see iron studies) and look for the cause: heavy periods, poor diet, or slow bleeding from the stomach or bowel.
Low MCV, high RBC count, normal RDW, Hb normal or slightly low	Often thalassaemia trait, which is harmless for you but important before pregnancy. An Hb electrophoresis or HPLC test confirms it. Iron tablets do not help and should not be taken unless ferritin is also low.
High MCV with low Hb	Often vitamin B12 or folate deficiency, very common in vegetarians and in people on metformin. Check B12, folate and thyroid (see vitamin B12 and folate).
Fever with low TLC and falling platelets	Typical of dengue in season, and also seen in typhoid and malaria. The doctor will usually repeat the CBC daily or on alternate days and watch for warning signs.
High eosinophils with itching, cough or tummy upset	Usually allergy or worms. A stool test and treatment for worms often settle it.
High TLC with high neutrophils and fever	Usually a bacterial infection; the doctor will look for where it is (urine, chest, skin, abdomen).

Get help today if

Fever with neutrophils below 1,000 (or TLC below 2,000), especially while on chemotherapy or carbimazole: go to hospital today.
Platelets below 20,000, or any count with bleeding from the gums or nose, red spots on the skin, or black stools: go to hospital today. With vomiting blood or heavy bleeding, call 112.
Dengue with severe tummy pain, repeated vomiting, bleeding, drowsiness or restlessness, cold hands and feet, or passing very little urine, often as the fever settles: go to hospital now, or call 112.
Haemoglobin below 7 g/dL, or any low haemoglobin with breathlessness at rest, chest pain or fainting: go to hospital today; with chest pain or fainting, call 112.

Call 112 or go to the nearest emergency department. Ambulance: 108 (102 in some states).

Questions people ask.

What does low MCV mean in a blood test?
Your red cells are smaller than usual. In India this is most often iron deficiency or thalassaemia trait. A ferritin test tells them apart: low ferritin means iron deficiency. If ferritin is normal and your RBC count is high, ask about a test for thalassaemia trait before taking iron.
Is a platelet count of 1.2 lakh dangerous?
Usually not. Without fever or bleeding it is often a temporary dip or clumping in the tube, and a repeat test a few weeks later is the next step. During a fever, especially in dengue season, the doctor will repeat it to see which way it is moving.
Why are my eosinophils high?
Most often allergies, asthma, eczema or intestinal worms, all common in India. A count slightly above the range with known allergies is usually nothing to worry about. A count above 1,500 per cumm, or one that stays high with symptoms, needs a doctor to look for the cause.
My lymphocytes are high and neutrophils are low. What does that mean?
Usually a viral infection, including a recent viral fever. Look at the absolute counts: often the lymphocytes are normal in number and only look high as a percentage because the neutrophils have dipped. A repeat CBC in two to four weeks usually shows both back to normal.
Do I need to fast for a CBC?
No. A CBC can be taken at any time of day. If other tests on the same sample need fasting, such as blood sugar or a lipid profile, fast for those.

Where this can be checked

These are trusted general sources. The advice on this page is Dr. Arya’s, written for patients in India. Ranges differ between labs: go by the range printed on your own report.

Your whole report, read by your doctor.

Send every page, old reports too. He reads them himself and tells you what changed and what to do.

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Dr. Prabhat Arya · MBBS, MD (Internal Medicine)