MCHC (mean cell hemoglobin concentration) in cats and dogs
MCHC (mean cell hemoglobin concentration) shows how densely red blood cells are filled with hemoglobin. A low value can come from young cells or iron deficiency but most often from sample changes; a high value is, according to eClinPath, always an artefact, because red cells cannot hold more hemoglobin than normal.
What it shows
MCHC is calculated: hemoglobin divided by hematocrit (or PCV). Unlike MCH, it does not depend on cell size: it describes how full the cells are, not how big they are. Together with MCV it sorts anemia into normochromic and hypochromic (normally filled or under-filled cells).
MCHC almost does not differ between species — the Merck Veterinary Manual gives about 330 g/L for all of them. Because it is built from two measurements, an error in either one shows up here first. Some analyzers also measure hemoglobin concentration inside cells optically (CHCM); when MCHC is unreliable, for example in a lipemic sample, the lab may rely on that value instead.
Higher than reference — what it may be a sign of
A high MCHC is a sign of a sample effect, not of disease in the cells themselves:
- Lipemia — the most frequent cause: fatty plasma makes measured hemoglobin falsely high, for example in blood taken soon after a meal.
- Hemolysis — in the tube or inside the vessels. Free hemoglobin is still measured, while hematocrit falls with the broken cells.
- Heinz bodies — clumps of damaged hemoglobin inside red cells; eClinPath mentions large numbers of them, in more than 50% of cells in cats.
- Other effects — red cell clumping (agglutination), many nucleated red cells, too much EDTA in an underfilled tube.
An implausibly high MCHC itself tells the vet that hemoglobin on this form may be inaccurate as well.
Lower than reference
- Swollen cells in the sample — the most common cause of a low MCHC, usually with a high MCV: cells swell during storage or when the blood is very concentrated (high sodium or sugar).
- Regenerative anemia — young cells hold less hemoglobin, but eClinPath notes this is not a consistent finding.
- Iron deficiency — under-filled cells may show on the smear before MCHC falls; by the time MCHC is low, the animal is usually anemic.
- Portosystemic shunts and, rarely, lead poisoning or copper and vitamin B6 deficiency.
Look at together with
- MCV — microcytic and hypochromic points to iron deficiency; a low MCHC with high MCV raises the question of a stored sample or of regeneration.
- Hemoglobin and hematocrit — the numbers MCHC is calculated from.
- Reticulocytes — whether the marrow is responding.
- Sample remarks on the form — lipemia, hemolysis — and the blood smear, which shows Heinz bodies and clumping.
Units and conversion
MCHC is reported in g/L (the SI unit; г/л on Russian-language forms) or in g/dL. 1 g/dL equals 10 g/L, so 33 g/dL is 330 g/L. Some forms print MCHC in % — it is the same number as in g/dL and converts to g/L the same way, × 10. In the app each row keeps the unit printed on the form, and the chart converts everything to one unit.
Reference range
The reference range is on your lab’s form. It depends on species and on the analyzer. Because a high MCHC is an artefact by nature, a value above the range is mainly a reason to look at the sample — was the plasma fatty, were cells broken — and to read hemoglobin from this test with caution. A low value is read together with MCV, reticulocytes and the age of the sample, and a repeat test often settles it.
Cats and dogs
In cats Heinz bodies are a typical reason for a falsely high MCHC: according to the Merck Veterinary Manual, cats are more susceptible to Heinz body formation than other species, and eClinPath lists large numbers of them — in more than half of the red cells — among the causes. Lipemia after a meal is another common feline sample effect. A low MCHC in a cat is read the same way as in a dog.
The sources give no separate canine rules for MCHC. In dogs, as in cats, a high value first sends the vet to the sample — lipemia and hemolysis. A low MCHC together with small red cells (low MCV) is the classic picture of iron deficiency, usually from chronic blood loss, or of a portosystemic shunt.
Add a lab form — Pet Tracker Space recognises the lines, keeps the form’s units and draws each indicator over time with your lab’s reference band.
Sources
This page explains what a lab value means. It is not a diagnosis and not a substitute for your veterinarian — only they can interpret results for your pet.