By The Pawline veterinary teamVeterinary-reviewed by Alastair Greenway, BVM&S MRCVS · 25 July 2026
Reference range · fL
6077
Reference
60–77
Direction
Both unusually high and low values carry meaning.
This is the conventional reference interval. Your pet’s own report may print a slightly different range — always read the value against that. Sign in to see your pet’s value on this strip.
MCV is the average size of the red blood cells. Small cells point towards iron issues or chronic disease; large cells often accompany a regenerative response to anaemia. It's one of the red-cell indices used to characterise what type of anaemia is present.
MCV (mean corpuscular volume) is the average size of a red blood cell. It is one of the red-cell indices — calculated figures that, together with MCH and MCHC, turn a bare anaemia into a characterised one. Cell size is a genuinely useful clue, because different processes make red cells bigger or smaller in recognisable ways.
MCV is the average red cell size. Small cells suggest iron issues or chronic disease; large cells often accompany a regenerative response to anaemia.
Reading a low MCV (small cells)
Small red cells (microcytosis) most classically point to iron deficiency — usually from chronic blood loss (a slow gut bleed, heavy parasites) — because iron-starved cells are made smaller. Some breeds (notably Akitas and Shiba Inus) normally have smaller red cells, and certain liver conditions (portosystemic shunts) also produce microcytosis. So a low MCV is a strong prompt to consider iron status and chronic blood loss.
Reading a high MCV (large cells)
Large red cells (macrocytosis) most often reflect a regenerative response: when the marrow is rushing out new red cells to replace those lost or destroyed, the young cells (reticulocytes) are larger, lifting the average. So a high MCV alongside an anaemia and a high reticulocyte count is a reassuring sign the marrow is responding. Some cats can show macrocytosis from specific causes, and it occasionally reflects other marrow conditions, so it is read in context.
In chronic disease
Tracked with the reticulocyte count, MCV helps follow the character of an anaemia over time — a rising MCV as the marrow mounts a regenerative response, or a persistently low MCV pointing at ongoing iron loss. It is always interpreted alongside whether the anaemia is regenerative or not.
Cat vs dog
MCV runs lower in cats than dogs (feline red cells are naturally smaller), so the reference ranges differ and are species-specific. The microcytosis-means-iron and macrocytosis-means-regeneration logic applies to both, with the breed and species baselines kept in mind.
How it's measured
MCV is calculated by the analyser from the haematocrit and the red cell count, reported in femtolitres (fL). It is read with MCH, MCHC, the RBC count and the reticulocyte count as a set. Read the value against your own report's range.
What to do next
A low MCV is a prompt to look for iron deficiency and chronic blood loss (and to consider breed baselines); a high MCV, read with the reticulocyte count, usually reflects a regenerative response to anaemia. As one of the indices, MCV is interpreted together with the rest of the red-cell picture to pin down the type of anaemia and its likely cause.
Reference ranges reflect conventional laboratory intervals. Always interpret against your own lab's printed range and your veterinary surgeon's judgement. A brighter optimal band is shown only where a published guideline defines one, and it is cited.
This page is educational and is not a diagnosis. Lab results are interpreted in the full clinical context by your veterinary surgeon; a single value rarely tells the whole story.
