MCHC in a blood test is your mean cell haemoglobin concentration: a measure of how densely packed with haemoglobin your red blood cells are, on average. Haemoglobin is the protein that carries oxygen around your body, so MCHC gives a quick indication of how well equipped your red cells are to do their job.
A result that sits just outside the range is common and often means very little. MCHC is one of the most stable numbers on a full blood count. That is why doctors pay attention when it moves a long way, and why they rarely act on a small shift by itself.
This guide covers what MCHC measures, how it differs from MCH and MCV, what low and high results can mean, and what to do if yours has been flagged.
Key Takeaways
- MCHC stands for mean cell haemoglobin concentration. It shows how concentrated the haemoglobin is inside your red blood cells.
- It is reported automatically as part of a full blood count (FBC), so it appears on your results even if nobody asked for it specifically.
- UK labs usually report MCHC in g/L, with a typical adult range of around 310 to 350 g/L. Always go by the range printed on your own report.
- A low MCHC most often points to iron deficiency. Your doctor will read it alongside MCV and MCH to rule out other causes.
- A high MCHC is uncommon. It can signal a red cell condition, but it is often caused by the sample itself.
- MCHC is rarely read on its own. Your doctor interprets it alongside haemoglobin, MCV and MCH.
What MCHC in a blood test actually measures
A full blood count looks at the three main types of cell in your blood: red cells, white cells and platelets. MCHC is one of several markers that describe your red cells.
It is calculated rather than counted directly. The analyser takes the amount of haemoglobin in your blood and divides it by the proportion of your blood made up of red cells, known as the haematocrit.
Think of it as concentration rather than quantity. Two people can have the same number of red cells, but if one person’s cells carry less haemoglobin for their size, their MCHC will be lower.
Under a microscope, cells with a low MCHC look paler than usual. Doctors call this hypochromia. Cells with a normal MCHC are described as normochromic.
MCHC, MCH and MCV: how they fit together
MCHC appears alongside several other red cell markers on your results. Each one answers a slightly different question.
| Marker | What it tells you | Usual UK unit |
| Haemoglobin (Hb) | The total amount of oxygen-carrying protein in your blood | g/L |
| MCV (mean cell volume) | The average size of your red cells | fL (femtolitres) |
| MCH (mean cell haemoglobin) | The average amount of haemoglobin in each red cell | pg (picograms) |
| MCHC (mean cell haemoglobin concentration) | How concentrated that haemoglobin is, relative to the size of the cell | g/L |
These markers usually move together. Iron deficiency, for example, tends to produce smaller cells (low MCV) carrying less haemoglobin (low MCH), and in more established cases a low MCHC as well. That pattern tells a doctor far more than any single number.
What is a normal MCHC level?
The first thing most people want to know about MCHC in a blood test is whether their number is normal. UK laboratories typically use an adult reference range of around 310 to 350 g/L. North Bristol NHS Trust’s Severn Pathology service, for example, quotes exactly that range, although some labs set theirs slightly differently.
Your result will be printed next to the range your own lab uses, and that is the range to go by.
Many of the websites that come up when you search for MCHC are American and quote results in g/dL. To compare, divide the UK figure by ten: 330 g/L is the same as 33 g/dL. So an MCHC of 36 g/dL (360 g/L) sits above most UK ranges, and 30 g/dL (300 g/L) sits below them.
What your MCHC number might mean
| Your result | What it suggests | What usually happens next |
| Below range (under about 310 g/L, or 31 g/dL) | Red cells carrying less haemoglobin than expected for their size | Your doctor checks haemoglobin, MCV, MCH and often ferritin to look for iron deficiency |
| Within range (about 310 to 350 g/L) | Normal haemoglobin concentration | No action on MCHC alone, although other markers still matter |
| Above range (over about 350 g/L, or 35 g/dL) | Uncommon, and often a sample effect | A repeat test is often the first step before looking for a red cell condition |
Children have different reference ranges. A flagged result in a child should always be discussed with their doctor.
What does a low MCHC mean?
A low MCHC means your red cells are carrying less haemoglobin than expected for their size. These are the main causes doctors consider:
- Iron deficiency anaemia. The most common cause. The NHS lists pregnancy and blood loss among the usual underlying reasons, including heavy periods and bleeding from a stomach ulcer or elsewhere in the gut. Conditions that affect how iron is absorbed, such as coeliac disease, can also play a part.
- Thalassaemia trait. Carriers usually have small red cells with a low MCH, but their MCHC is often normal or only slightly low. That difference is one of the clues doctors use to tell it apart from iron deficiency. The NHS notes that being a carrier does not generally cause health problems, although it matters if you are planning a family.
- Anaemia of chronic disease. Long-term inflammation, for example from Crohn’s disease, or ongoing infection or kidney disease can affect how the body uses its iron. MCHC is often normal in this type of anaemia, but it can be low.
If the cause is anaemia, you may notice tiredness, shortness of breath, palpitations, headaches or pale skin. Many people with a mildly low MCHC have no symptoms at all.
What does a high MCHC mean?
A genuinely high MCHC is unusual, because a red cell can only hold so much haemoglobin. When a result comes back high, the first question is often whether the sample is the problem rather than your blood.
- Sample or analyser effects. Cold agglutinins (antibodies that make red cells clump in cooler temperatures), very fatty samples and damaged red cells in the tube can all push the figure up. A repeat test often resolves it.
- Hereditary spherocytosis. An inherited condition in which red cells are sphere-shaped rather than disc-shaped, which makes them more fragile.
- Autoimmune haemolytic anaemia. The immune system breaks down red cells faster than normal.
What to do if your MCHC result is flagged
An out-of-range MCHC in a blood test is a prompt for a conversation, not a diagnosis. These steps help you get the most from it.
- Look at the rest of the full blood count. A flagged MCHC with normal haemoglobin, MCV and MCH is often a minor variation.
- Expect further tests if other markers are out too. Depending on the pattern, your doctor may suggest iron studies (including ferritin), vitamin B12, folate or a blood film.
- Do not start iron supplements on the strength of MCHC alone. Iron can hide the underlying cause of a problem, and it will not help if the cause is thalassaemia trait.
- Talk the results through with a GP. At MyHealthcare Clinic, all blood test results are reviewed by our GPs, who explain what the numbers mean for you and recommend next steps where they are needed. You can also book a GP appointment to go through results from elsewhere.
For a broader look at what each part of your results covers, read our guide to what a blood test shows.
Want to check your red cell markers? A Full Blood Count covers MCHC, MCH and MCV. If you are feeling run down or a previous result suggested anaemia, our Anaemia Screen adds iron studies (including ferritin), vitamin B12, folate and an inflammation marker. For ongoing tiredness, the Tired Screen is broader still. All three are available on our private blood tests page, with results reviewed by a GP.
When a private blood test is not the right starting point
A private full blood count is a quick, convenient way to check your red cell markers. It is not the right route for everyone.
If you want to know whether you carry thalassaemia, a full blood count can raise the question but cannot answer it. A specific haemoglobin test is needed.
If you feel acutely unwell, for example breathless at rest, faint or with chest pain, call 999 or go to A&E. If you need help urgently but it is not an emergency, contact NHS 111.
If you are already under a haematologist or other specialist, speak to that team before arranging separate tests, so your results are not interpreted in isolation.
If you are pregnant, your antenatal team will already be checking your blood count as part of routine care.
Check your full blood count with MyHealthcare Clinic
If your MCHC has been flagged, or you simply want a clearer picture of your health, a full blood test is a straightforward place to start. For a wider view, our health checks combine blood tests with a GP consultation, and our guide to yearly health checks explains why a regular check is worth it.
Book at one of our clinics in London or across England, and a GP will review your results with you.
FAQs
Is a low MCHC serious?
Usually not on its own. A slightly low MCHC is common and often reflects early or mild iron deficiency, which is very treatable once the cause is found. It becomes more significant when haemoglobin is also low, or when the reason for iron loss is unexplained.
What is the difference between MCH and MCHC?
MCH is the average amount of haemoglobin in each red cell. MCHC is how concentrated that haemoglobin is, relative to the size of the cell. Small cells can have a low MCH but a normal MCHC, because there is less haemoglobin in a smaller space.
Do I need to fast for a full blood count?
No. A full blood count does not require fasting. If it is taken alongside other tests, such as some glucose or cholesterol tests, you may be asked to fast for those.
Can MCHC change quickly?
Not usually. Red blood cells live for around 120 days, so MCHC tends to change gradually. A sudden change between two tests taken close together is more likely to reflect the sample than a real change in your blood. Having regular blood tests makes it much easier to tell a genuine trend from a one-off result.
Can I get a full blood count without a GP referral?
Yes. You can book a full blood count directly at MyHealthcare Clinic, with same-day appointments available six days a week, and one of our GPs will review your results. If you would rather start with a conversation, our guide on how to get a private GP appointment explains your options.