A high MCV means your red blood cells are on average larger than normal, usually above 100 fl. The medical term is macrocytosis. Of every value in your blood count, this is the one you can least wave away with "I trained hard yesterday", because training barely changes your MCV.
That is exactly what makes it valuable.
Where your haemoglobin and your white cells swing around with your training schedule, your MCV sits there fairly unmoved. If it is high, there is usually another reason. And that reason is worth chasing.
What is a normal MCV value?
Most Dutch labs use roughly 80 to 100 fl (femtolitres) as the reference. Below 80 your cells are called microcytic, above 100 macrocytic. MCV stands for mean corpuscular volume. Unlike MCH it is not a calculation: modern cell counters measure the volume of each red blood cell directly and report the mean. Your haematocrit is what gets calculated from it, as MCV times your red blood cell count.
Always read the range on your own result, because labs differ.
And do not read the MCV alone. It only becomes informative next to your haemoglobin and your MCH.
What does an MCV of 89, 92 or 97 mean?
All three are normal, and that is not the whole answer. The middle of the reference band sits higher than most people assume, so a reading of 89 fl or 92 fl is not a borderline value you just get away with. It is roughly where the average adult sits.
That is because the median MCV climbs slowly with age. In an analysis of 977,335 measurements from people without anaemia at a single South Korean hospital, the median was 89.9 fl between 20 and 29, 91.2 fl between 40 and 49, and 93.0 fl above eighty (PMID 35599236). The middle half of the twenty-somethings fell between 87.4 and 92.5 fl, and of the forty-somethings between 88.5 and 93.9 fl. So an MCV of 89 fl is almost exactly the median in your twenties, 90 fl or 92 fl is ordinary mid-range in your forties, and 94 fl and 97 fl sit in the upper half of normal rather than outside it.
| Your MCV (fl) | What it is called | What it usually means |
|---|---|---|
| below 80 | microcytic | smaller cells; iron deficiency is the most common explanation, and ferritin is the next value |
| 80 to 90 | normocytic, lower end | normal, but low in the band; with symptoms alongside, your iron status is the logical follow-up |
| 90 to 98 | normocytic, middle | normal; this is where most adults sit, and the share grows with age |
| 98 to 100 | normocytic, upper end | still normal; it only gets interesting above 100 |
| above 100 | macrocytic | larger cells; alcohol, vitamin B12 and folate are the first questions |
A number from that table is not a diagnosis, and a shift within the band often says more than the position itself. Going from 88 to 97 fl in a year is a change, even though both readings stay comfortably normal. What your MCV actually measures, and how the lab arrives at it, is on our page about the MCV blood value.
Why a normal MCV does not rule out a deficiency
This is the most important pitfall of the value, and it sits in the word average. If you have an iron deficiency and a vitamin B12 or folate deficiency at the same time, your bone marrow makes both undersized and oversized cells. In the average they cancel out. Your MCV lands neatly on 90 fl while two deficiencies exist side by side.
Your RDW does give it away. The MCV gives you the average, the RDW gives you the spread around it. A normal MCV with a clearly raised RDW is exactly the pattern a combined deficiency produces, which is why those two values should never be read apart.
In practice: if you are tired without an obvious reason and your MCV is normal, that on its own is not reassurance. Having ferritin, vitamin B12 and folate measured alongside it tells you more than looking at the same average again.
What causes a high MCV?
In Dutch general practice the two best known causes are alcohol and a deficiency of vitamin B12 or folate. Research among Dutch primary care patients with macrocytic anaemia found exactly that pattern: a shortage of B12 or folate and excessive alcohol use are among the most common explanations (PMID 27542607).
Alcohol enlarges your red cells even without a vitamin deficiency. It is a direct effect on your bone marrow, and one of the earliest traces drinking leaves in your blood.
| Possible cause | What you often see alongside | What you want measured with it |
|---|---|---|
| Regular alcohol use | MCV mildly to moderately raised, sometimes raised gamma-GT | Liver values |
| Vitamin B12 deficiency | MCV high, sometimes tingling or fatigue | Vitamin B12 |
| Folate deficiency | A picture similar to B12 | Folate |
| Underactive thyroid | MCV mildly raised, tiredness, cold intolerance | TSH |
| Liver disease | Raised liver values | ALT, AST, gamma-GT |
| Certain medicines | An isolated raised MCV | Bring your medication list |
A raised MCV without anaemia is common, and not automatically alarming. Research among middle-aged and older adults found that macrocytosis is by no means always linked to a vitamin deficiency (PMID 24244281).
Why is a high MCV in athletes a reason to look further?
Because the usual sporting explanation does not apply here. With your haemoglobin, haematocrit and white cells you can often attribute a deviation to dilution or to yesterday session. With your MCV you cannot: it barely moves with your training schedule.
That makes a raised MCV in an athlete relatively more informative than in anyone else. There is less noise to cross out.
Take a strength athlete with an MCV of 103 fl, a normal haemoglobin and otherwise fine values. There is no training explanation. There are, however, three glasses of wine an evening, or a plant-based diet without B12 supplementation. Those are the questions that belong on the table.
I watch athletes panic over a haemoglobin that dropped through dilution, and look straight past an MCV of 104. That is exactly the wrong order.
Can a high MCV be harmful?
The MCV itself is not a disease; it is a clue. Large red cells usually do their job perfectly well, and many people with a mildly raised MCV notice nothing at all. What sits underneath it may deserve treatment, which is why a raised value is a reason to look further rather than to ignore.
A B12 deficiency that persists for a long time can cause nerve symptoms, for instance. That is not something to sit out.
The NHG guideline on anaemia describes macrocytosis as a finding that calls for an explanation. Not as a diagnosis, but not as noise either.
When should you discuss a raised MCV with your GP?
Almost always, and certainly if it stays above 100 fl on a repeat measurement. This is the value in your blood count I would take least lightly. Especially combined with fatigue, tingling in hands or feet, or if you drink regularly.
Take your whole blood count with you, and your medication list. An isolated raised MCV calls for a different route than a raised MCV with anaemia alongside it (PMID 17619679).
And be honest about your drinking. Your MCV has already been honest about it.
Where do you start?
Have your MCV repeated and your vitamin B12 measured with it. Those two numbers together almost always give direction. Our complete blood count test gives you MCV, MCH and the rest of the red series, with an assessment by a BIG-registered doctor.
How to read all the values together is in complete blood count explained. What your MCH says about your iron is in the MCH value. What alcohol does to your blood values and your recovery is in alcohol and your blood values, and the B12 side is in vitamin B12 and energy.
References
- Croonen EA, et al. Prevalence of potential underlying aetiology of macrocytic anaemia in Dutch general practice. BMC Family Practice. 2016. PMID 27542607.
- Haematinic deficiency and macrocytosis in middle-aged and older adults. PLoS One. 2013. PMID 24244281.
- Macrocytosis, an Australian general practice perspective. Australian Family Physician. 2007. PMID 17619679.
- NHG. NHG guideline on anaemia. Accessed 2026.
- RIVM. Blood testing and reference values. Accessed 2026.
- Lee JY, Choi H, Park JW, Son BR, Park JH, Jang LC, Lee JG. Age-related changes in mean corpuscular volumes in patients without anaemia: an analysis of large-volume data from a single institute. Journal of Cellular and Molecular Medicine. 2022;26(12):3548-3556. PMID 35599236.
Disclaimer
Every blood test result includes a professional assessment by a BIG-registered doctor. This article gives general information and is not a substitute for medical advice. For treatment decisions, discuss your results with your GP.
Często zadawane pytania
What is a good MCV value?
Between 80 and 100 fl, and within that band most adults sit in the upper half. In a large South Korean hospital dataset the median rose with age: around 89.9 fl in your twenties and 93.0 fl above eighty. A reading of 92 or 94 is therefore not a borderline value but ordinary mid-range. Always check the reference printed on your own result, because labs differ from one another.
What does a high MCV value mean?
Above 100 fl your red blood cells are called macrocytic: they are larger than normal on average. In Dutch general practice alcohol and a vitamin B12 or folate deficiency top the list, with thyroid, liver and certain medicines behind them. It is a clue, not a diagnosis. A repeat measurement with your B12 alongside it usually gives direction quickly.
What does it mean if your MCH is high?
MCH is the amount of haemoglobin per red blood cell, and it often moves with your MCV, because larger cells hold more haemoglobin. A raised MCH therefore usually points the same way as a raised MCV, towards vitamin B12, folate or alcohol. The full explanation, including what a low MCH says about your iron, is in our article on the MCH value.
What does MCV stand for in a blood test?
MCV stands for mean corpuscular volume, the average volume of a single red blood cell, expressed in femtolitres (fl). Modern cell counters measure the volume of each red blood cell directly and report the mean; your haematocrit is calculated from that instead. It comes as standard with a complete blood count, alongside MCH, MCHC and RDW, so it costs you no extra tube of blood.
Is an MCV of 104 something to worry about?
An MCV of 104 fl sits just above the reference and is called mildly macrocytic. On its own that says little: many people with this value notice nothing, and a tube left standing for a day already produces an artificially higher MCV. What counts is the rest of your blood count and whether a repeat measurement stays there. Discuss it with your GP.
How long does a raised MCV take to fall after you stop drinking?
Slowly, because you cannot speed up the cells you already have. Red blood cells live around 120 days and your MCV falls at roughly that pace, so expect weeks up to about three months before the value is back to normal. Do not remeasure after a fortnight and draw a conclusion from it. A check at three months tells you more.
Autor
Enhanced Health
Dr. Naimi, lekarz wpisany do holenderskiego rejestru BIG, nadzoruje standardy medyczne naszych treści i ocen. Przeczytaj naszą politykę medyczną
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