If your MCHC is low, your red blood cells hold too little haemoglobin for their volume. At most labs the range sits around 320 to 360 g/l. A low MCHC usually fits iron deficiency, and then travels with a low MCH and a low MCV.
But there is something about MCHC you will read on almost no other page.
Of every value in your blood count, this is the one most often skewed by a technical cause rather than a medical one. The tube, the temperature, the fat in your blood. That makes it awkward to read, and worth explaining properly.
What is MCHC?
MCHC stands for mean corpuscular haemoglobin concentration. It is the amount of haemoglobin divided by the volume holding it, so a concentration. Where MCH tells you how much haemoglobin a cell contains, MCHC tells you how densely it is packed.
Dutch labs report the value in g/l or in mmol/l. In g/l the range runs roughly from 320 to 360, in mmol/l from about 20 to 22.
So check which unit is on your form first. Otherwise you are comparing two unrelated numbers.
The value belongs to the complete blood count, beside your MCH and your MCV.
What is a normal MCHC value?
In adults the reference range usually runs from 320 to 360 g/l, with barely any difference between men and women. The spread is narrower than for the other indices, which means a small deviation stands out sooner here than in your haematocrit.
| Your MCHC in g/l | How to read it |
|---|---|
| below 300 | clearly low |
| 300 to 319 | low |
| 320 to 360 | in range |
| 361 to 370 | just above range, think about the sample first |
| above 370 | raised, almost always technical or spherocytosis |
Those last two rows are why this page exists. A high MCHC is rarely what people assume it is.
What does a low MCHC mean?
A low MCHC means your red blood cells are relatively pale. Iron deficiency is the usual cause, because less haemoglobin is built into each cell without iron. In a longer-standing shortfall your ferritin falls first, then your MCV and MCH, and your MCHC only last.
That is why a low MCHC is almost never the first signal. By the time it drops, something else has usually dropped already.
Chronic inflammation and thalassaemia also produce lower values. Thuisarts and the NHG guidelines describe how GPs separate those routes.
To find out whether iron is the cause, your ferritin shows it earliest.
Why a high MCHC is often the tube, not you
An MCHC above roughly 370 g/l is barely possible biologically, because haemoglobin would crystallise at that concentration. When a lab sees such a value, the first thought is nearly always that something happened to the sample rather than to the patient.
Four things produce that pattern.
- Haemolysis: red cells broken inside the tube, releasing haemoglobin.
- Lipaemia: a lot of fat in the blood, for instance after a fatty meal, which disturbs the optical measurement.
- Cold agglutinins: antibodies that clump red cells at room temperature.
- A tube stored too long or mixed poorly.
In those cases nothing about your blood has changed. Only the measurement.
Picture two people who both get an MCHC of 375 g/l back. For one the tube sat a day too long, for the other it did not.
Only the second result means anything.
If a strongly raised MCHC comes back, ask whether the test can be repeated on a fresh sample. That is a normal and reasonable request.
When a high MCHC does mean something
If the MCHC stays raised on a fresh sample, hereditary spherocytosis is the condition doctors think of first. In it, red blood cells are spherical rather than disc-shaped, so they hold the same haemoglobin in a smaller volume. The concentration therefore rises.
That combination has long been used as a screening signal. Work from 1997 showed automated erythrocyte indices can detect spherocytosis (PMID 9202619), and later studies confirmed the value of blood cell parameters for it (PMID 30945356).
More recent overviews describe how the diagnosis is made today (PMID 39467036).
Spherocytosis is rare and often inherited. If anaemia, jaundice or a removed spleen runs in your family, that is relevant information for your GP.
Which values do you read beside your MCHC?
MCHC is the least self-sufficient of the red cell indices. Always read it with your MCH, your MCV and your RDW, and check whether they tell the same story. If only the MCHC is off while the rest are normal, a technical cause is likely.
- MCV for the size of your red blood cells.
- RDW for how much they vary in size.
- Haemoglobin for total oxygen-carrying capacity.
These indices are part of the blood count in our basic health checkup, and you can add them individually through your own custom blood test.
My advice on this value: do not react to a high MCHC before you know the sample was sound. Ask for a repeat first, then discuss a persistent deviation with your GP.
This information is general and does not replace medical advice. Blood results from Vitalcheck are reviewed by a BIG-registered doctor. Always discuss an abnormal result with your own GP.
References
- Blood cell parameters for screening and diagnosis of hereditary spherocytosis. J Clin Lab Anal, 2019. PMID 30945356
- Screening for hereditary spherocytosis by use of automated erythrocyte indexes. J Pediatr, 1997. PMID 9202619
- Overview on Hereditary Spherocytosis Diagnosis. Int J Lab Hematol, 2025. PMID 39467036
- NHG guidelines and Thuisarts, on anaemia in Dutch primary care
Autor
Vitalcheck
Dr. Naimi, lekarz wpisany do holenderskiego rejestru BIG, nadzoruje standardy medyczne naszych treści i ocen. Przeczytaj naszą politykę medyczną
