---
title: "MCH vs MCHC: what each red-cell index measures, and which one to read"
type: biomarker-comparison
url: "https://www.test-well.com/biomarkers/compare/mch-vs-mchc"
biomarkers:
  - MCH
  - MCHC
reviewed_at: 2026-11-05
review_status: reviewed
date_published: 2026-11-04
---

# MCH vs MCHC: what each red-cell index measures, and which one to read

> Both are calculated red-cell indices on every CBC. MCH (mean corpuscular hemoglobin) is the average mass of hemoglobin in one red cell — hemoglobin divided by the red-cell count, in picograms — so it mostly tracks cell size: small cells carry less. MCHC (mean corpuscular hemoglobin concentration) is hemoglobin divided by hematocrit, the concentration of hemoglobin inside the cell in g/dL, and it changes only when cells are genuinely under-filled (iron deficiency, thalassemia) or over-concentrated (hereditary spherocytosis, a sample artifact). Low MCH with low MCV is the usual pattern of iron deficiency; MCHC is the index that adds information when it is high.


## MCH vs MCHC side by side

|  | MCH | MCHC |
| --- | --- | --- |
| What it measures | Average hemoglobin mass per red cell (hemoglobin ÷ red-cell count), in picograms | Average hemoglobin concentration inside the red cells (hemoglobin ÷ hematocrit), in g/dL |
| Normal range (adults) | age 18+: 27 – 33 pg | age 18+: 32 – 36 g/dL |
| What it mostly tracks | Cell size — it rises and falls with MCV, because bigger cells hold more hemoglobin | How full the cells are, independent of their size |
| A low value points to | Small, pale cells: iron deficiency, thalassemia trait, anemia of chronic disease, lead exposure | Hypochromia — iron deficiency once it is established, thalassemia; it is a later change than low MCH |
| A high value points to | Large cells: vitamin B12 or folate deficiency, alcohol, liver or thyroid disease, some medications, reticulocytosis | Hereditary spherocytosis, sickle cell disease, or an artifact — cold agglutinins, lipemia, hemolysis in the tube, very high white counts |
| Which to read first | Read with MCV; it rarely says anything MCV has not already said | Read when it is high (a specific finding) or when MCV is normal but MCHC is low (early iron deficiency) |
| What corrects it | Treating the cause of the size change — iron, B12 or folate, stopping alcohol | The same; a high MCHC from spherocytosis does not change and is managed by hematology |


## Why MCH mostly follows MCV

Hemoglobin concentration inside a red cell is held within a narrow band, so the amount of hemoglobin a cell carries is largely a function of how big the cell is. That makes MCH almost redundant with MCV: in iron deficiency and thalassemia the cells are small and MCH is low; in B12 or folate deficiency the cells are large and MCH is high. Clinicians read MCV and glance at MCH to confirm it agrees.

The one situation where MCH and MCV part ways is a mixed picture — iron deficiency together with B12 deficiency, or a thalassemia trait with a high reticulocyte count — where the MCV can land in the normal range while the RDW is wide and MCH is low. There, the blood smear and ferritin settle it.

## When MCHC adds information

MCHC is the index with its own meaning. Because it is a concentration, it stays normal in most anemias, and a genuinely high value (above about 36 g/dL) is a short list: hereditary spherocytosis, where cells lose membrane and become dense; sickle cell disease; and artifacts — cold agglutinins clumping cells, a lipemic or hemolyzed sample, or a very high white count — which the lab usually flags and which disappear on a repeat.

A low MCHC (under 32 g/dL) means the cells are under-filled with hemoglobin — hypochromia — which is classic for iron deficiency and thalassemia. It tends to fall later than MCV and MCH in iron deficiency, so a low MCHC with a normal MCV is unusual and prompts a look at [ferritin](https://www.test-well.com/biomarkers/ferritin/low) and a smear.

## Reading the pair with MCV and RDW

Four combinations cover most reports:

- Low MCH, low MCV, low or low-normal MCHC, high RDW — iron deficiency until ferritin says otherwise; a normal RDW with the same indices suggests thalassemia trait instead.
- High MCH, high MCV, normal MCHC — a macrocytic process: B12 or folate deficiency, alcohol, liver disease, hypothyroidism, hydroxyurea and other drugs, or a brisk reticulocyte response.
- Normal MCH and MCV, high MCHC — spherocytosis or an artifact; the smear shows spherocytes if it is real, and a repeat sample clears an artifact.
- All three normal with a low hemoglobin — a normocytic anemia: recent blood loss, kidney disease, inflammation or a marrow problem; the reticulocyte count is the next test.

## What to do about an abnormal MCH or MCHC

Neither index is treated on its own; each points to a cause. Low values lead to ferritin, iron studies and, when ferritin is normal, hemoglobin electrophoresis for thalassemia trait before anyone prescribes iron. High MCH leads to B12, folate, liver and thyroid tests. A high MCHC leads to a repeat sample and a smear, and to hematology if spherocytes are seen. If the hemoglobin is normal and the indices are only slightly off, a repeat CBC in a few weeks is often all that is needed.

## How do you test MCH and MCHC?

| Test or panel | Type | Price | Fasting | Results |
| --- | --- | --- | --- | --- |
| [Biological Age Panel](https://www.test-well.com/tests/biological-age-panel) | Panel (3 tests) | $59.99 | Yes | 1–3 business days |
| [General Wellness Panel](https://www.test-well.com/tests/general-wellness-panel) | Panel (4 tests) | $49.99 | Yes | 1–3 business days |
| [Blood Clotting Panel](https://www.test-well.com/tests/blood-clotting-panel) | Panel (4 tests) | $149.99 | No | 3–7 business days |
| [CBC with Differential Test](https://www.test-well.com/tests/cbc-with-differential) | Test | $17.99 | No | 1–3 business days |

Plus one $6 lab processing fee per order; physician authorization included.

## Common questions

### Which is more important, MCH or MCHC?

For most purposes neither — MCV carries the information about cell size and both indices follow it. MCHC matters when it is high, because that is a specific finding (spherocytosis, sickle cell, or an artifact), and when it is low with a normal MCV, which can be an early sign of iron deficiency. MCH rarely tells you anything beyond what MCV already has.

### Can MCH be low and MCHC normal?

Yes, and it is common early in iron deficiency and in thalassemia trait: the cells shrink first, so MCH (hemoglobin per cell) falls with MCV while the concentration inside the smaller cell is still normal. MCHC drops later as the cells become genuinely under-filled. A low MCH with a normal MCHC is read as a small-cell picture and worked up the same way.

### What causes high MCHC?

Most often a laboratory artifact — cold agglutinins, a lipemic or hemolyzed sample, a very high white count — which a repeat draw clears. True causes are hereditary spherocytosis and sickle cell disease, in which the red cells are abnormally dense. Severe dehydration does not raise MCHC meaningfully. A value above about 36 g/dL that persists on repeat should be looked at with a blood smear.

### Do I need treatment for a low MCH?

Not for the number — for its cause. A low MCH with a low ferritin is iron deficiency and is treated with iron and a search for the source of loss; a low MCH with a normal ferritin and a normal RDW is often thalassemia trait, which needs no treatment and should not be given iron. If hemoglobin is normal and MCH is only slightly low, a repeat CBC and a ferritin are the whole plan.

## Related

- [MCH: reference range and what high or low means](https://www.test-well.com/biomarkers/mch)
- [MCHC: reference range and what high or low means](https://www.test-well.com/biomarkers/mchc)
- [Hemoglobin vs Hematocrit: what's the difference?](https://www.test-well.com/biomarkers/compare/hemoglobin-vs-hematocrit)
- [Lab results explainer](https://www.test-well.com/tools/lab-results-explainer)

## Sources

- [Sarma, Red Cell Indices — Clinical Methods: The History, Physical, and Laboratory Examinations, 3rd edition (NCBI Bookshelf)](https://www.ncbi.nlm.nih.gov/books/NBK260/)
- [Camaschella, Iron-Deficiency Anemia (NEJM 2015)](https://doi.org/10.1056/NEJMra1401038)
- [Merck Manual Professional Edition — Evaluation of Anemia](https://www.merckmanuals.com/professional/hematology-and-oncology/approach-to-the-patient-with-anemia/evaluation-of-anemia)
- [AACC Lab Tests Online](https://www.testing.com/tests/red-blood-cell-indices/)
- [MedlinePlus (NIH) — RBC indices](https://medlineplus.gov/ency/article/003648.htm)

---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-11-05. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md

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