MCV and Ferritin Pattern Viewer: Small or Large Red Cells

MCV (mean cell volume) tells you whether the red blood cells are, on average, small, normal-sized or large. A normal MCV is about 80–100 fL, and above 100 fL is called macrocytosis.1 Ferritin is the single most useful marker of iron deficiency anaemia.3 This viewer shows which of the patterns described in my articles your MCV and ferritin resemble, and which causes the research lists for that pattern. It does not diagnose, and it does not tell you what to do.

This tool does not interpret your results for you. Lab values must be interpreted by your own doctor together with your symptoms, history and examination.

MCV (fL)
Ferritin (µg/L = ng/mL)
Hemoglobin compared with your lab’s reference range
CRP
Blood taken within a few hours of a long or hard training session or race?

Why MCV and ferritin are read together

MCV shows the size of the red cells but not why they are that size.2 Ferritin reflects iron stores, but it rises with inflammation, so a normal ferritin can hide iron deficiency when inflammation is present.3 Read together, they help separate the main patterns: small cells with low ferritin, small cells with normal iron studies, normal-sized cells with low ferritin, and large cells.1,3 For transferrin saturation and haemoglobin, use the Iron Panel Pattern Viewer.

Thresholds used

MCV: about 80–100 fL is the usual range and above 100 fL is macrocytosis;1 microcytosis is defined as below 80 fL in North America and below 85 fL in UK practice.4 This tool uses 80 fL. Ferritin: below 15 µg/L indicates absent iron stores, below 30 µg/L generally indicates low stores, 45 µg/L has been suggested as a cut-off when inflammation is present, and above 150 µg/L absolute iron deficiency is unlikely.3 Your laboratory’s own reference ranges apply to your results.

References

Every figure and statement in this tool is linked to a source: the original study where my article cites one, otherwise my own article on the topic. The small numbers in the text refer to this list.

  1. Dr. Antti Rintanen: MCV Blood Test High: What It Means and the Most Common Causes
  2. Dr. Antti Rintanen: Microcytic Anemia: Causes, Key Blood Tests and Treatment Explained
  3. Snook et al. 2021. British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults. Gut.
  4. Bailey et al. Microcytosis and cancer risk in UK primary care. Br J Gen Pract.
  5. Weiss, Ganz and Goodnough 2019. Anemia of inflammation. Blood.
  6. Sarma. Red Cell Indices. In: Clinical Methods, 3rd edition. NCBI Bookshelf.
  7. Study of red blood cell indices in 31 amateur runners after a half-marathon (PMC4147199), cited in my MCV article.
  8. Sports-medicine review describing “sports anemia” as dilutional pseudoanaemia (PMC8472039), cited in my MCV article.

Sources

This tool is based on the articles below and the studies cited in them:

This tool is for general education. It does not diagnose, interpret your own results, give personal recommendations or replace an assessment by your doctor.