Key takeaways
- MCHC shows how concentrated the haemoglobin is inside your red blood cells, and it's reported on every full blood count.
- It's calculated from your haemoglobin and haematocrit, so it always sits alongside MCV and MCH.
- A low MCHC is most often linked to iron deficiency.
- A high MCHC more often reflects how the sample behaved in the laboratory than a real change in your red cells.
- If your MCHC is flagged, an iron status profile or a ferritin test can help find out why.
Your full blood count has come back, and one line near the bottom, MCHC, has a small H or L next to it. Most people have never heard of it until that moment.
MCHC stands for mean corpuscular haemoglobin concentration. It's the average concentration of haemoglobin inside your red blood cells, and it's shown on every full blood count (FBC). On its own it rarely changes a diagnosis. A doctor reads it alongside your haemoglobin, MCV and MCH, and a full blood count is a sensible starting point for that wider look.
Book a full blood count at 117a Harley Street: £63.75 plus the £50 blood draw, results in 1 day.
What does MCHC actually measure?
Haemoglobin is the protein in red blood cells that carries oxygen. MCHC measures how much of it is packed into a given volume of red cells, as a concentration rather than an amount. Put simply, it asks: for the red cells you have, how full of haemoglobin are they?
The laboratory doesn't run a separate test for it. It works MCHC out from your haemoglobin and haematocrit results, or equivalently from MCH relative to MCV.
MCHC vs MCH vs MCV: what's the difference?
All three describe your red blood cells, but each looks at a different property.
| Marker | What it measures |
|---|---|
| MCV (mean corpuscular volume) | The average size of your red blood cells |
| MCH (mean corpuscular haemoglobin) | The average amount of haemoglobin inside a single red blood cell |
| MCHC (mean corpuscular haemoglobin concentration) | How concentrated that haemoglobin is within the cell, taking the cell's size into account |
Because the three are related, a clinician reads them together. A low MCV and low MCH often appear alongside a low MCHC, for example, and that pattern points somewhere more clearly than any one marker could.
What can a low MCHC mean?
A low MCHC most often points to iron deficiency, because your body needs iron to make haemoglobin. When iron runs short, red cells end up with less haemoglobin packed inside. That shows up as a lower MCHC, usually with a low MCH and often a low MCV. Less often, an inherited condition such as thalassaemia trait produces a similar pattern.
A low MCHC on its own, with your other red cell markers normal, isn't always significant. Your clinician can tell you whether it needs following up with further tests.
What can a high MCHC mean?
A high MCHC is less common. It's more often about how the sample behaved during processing than a genuine change in your red cells. High levels of certain proteins or fats in the blood can push the measured MCHC up without your cells carrying any extra haemoglobin.
Less often, a genuinely high MCHC is seen when red cells are an unusual shape, as in hereditary spherocytosis, or when they're breaking down faster than usual. So a raised MCHC is often repeated to confirm it's real, and it's worth talking any unexpected result through with a clinician.
What to test next if your MCHC is flagged
The next step usually depends on what else is unusual on your full blood count, and on how you feel. Each of these follow-up tests is priced plus the £50 blood draw.
- An anaemia blood test profile checks your red cells along with the iron, folate and vitamin B12 needed to make them. It's useful when a low MCHC comes with low haemoglobin: £226.25, results in 2 days.
- An iron status profile looks at how much iron is in your blood, how much is stored and how well it's being carried: £126.25, results in 1 day.
- A standalone ferritin blood test checks how much iron you have stored. It's often the first thing a clinician wants to see if iron deficiency is suspected: £68.75, results in 1 day.
Getting a full blood count on Harley Street
A full blood count needs no fasting or special preparation, and results usually arrive by email in 1 day. Like all our private blood tests in London, you can self-request it without a GP referral, book online or walk in to 117a Harley Street seven days a week. Start your booking.
Frequently asked questions
What is a normal MCHC range?
Your report shows the laboratory's own reference range next to your MCHC result, and that range decides whether yours counts as high or low. If it sits outside, ask your clinician to talk you through what it means for you.
Is a slightly low MCHC something to worry about?
Not necessarily. A slightly low MCHC, with your other red cell markers normal, is often not significant. Your clinician can say whether it needs any follow-up.
Can dehydration change MCHC?
Not usually. Dehydration can raise haemoglobin and haematocrit together, and because MCHC compares the two, it normally stays the same.
Do I need to fast for a full blood count?
No. There's no fasting or other preparation, so you can eat and drink normally beforehand.
How quickly will I get my full blood count results?
Usually in 1 day, sent to you by email.
Will a doctor explain my results?
Yes, if you add a doctor review to your test, which costs £75 at Blood London. For a full consultation about an abnormal result, you can book a private GP consultation at Medical Express Clinic, which costs £150.
References
- NHS: Blood tests
- Lab Tests Online UK: Full blood count (FBC)
- NICE Clinical Knowledge Summaries: Anaemia, iron deficiency
- NHS: Iron deficiency anaemia