MCH — Normal Range & Interpretation

Clinical Context

Mean corpuscular hemoglobin (MCH) measures the average mass of hemoglobin contained within a single red blood cell. The value parallels MCV in most clinical scenarios and helps NPs classify anemias as hypochromic, normochromic, or hyperchromic. MCH works alongside MCV, MCHC, and RDW to narrow the differential when hemoglobin falls below the reference range.

Low MCH signals hypochromic anemia and points toward iron deficiency, thalassemia, chronic blood loss, or anemia of chronic disease in advanced stages. Elevated MCH accompanies macrocytic anemias driven by vitamin B12 deficiency, folate deficiency, alcohol use, hypothyroidism, and certain medications including methotrexate and hydroxyurea. Hereditary spherocytosis also raises MCH because dense, small cells concentrate hemoglobin.

On the AANP exam, expect to pair MCH with MCV when interpreting a CBC. Expect vignettes that present a fatigued patient with low hemoglobin and ask the candidate to distinguish microcytic hypochromic iron deficiency from macrocytic findings of B12 or folate deficiency. Questions link low MCH to heavy menses, GI bleeding, or poor dietary iron intake, and link high MCH to strict vegan diets, pernicious anemia, and chronic alcohol use. Know which confirmatory labs to order next, such as ferritin, B12, folate, and peripheral smear.

Practice Questions

Related Labs

• WBC — /μL
• RBC — /μL
• Hemoglobin (Hgb) — g/dL
• Hematocrit (Hct) — %
• Platelets — /μL

Sources

• MedlinePlus
• ARUP Consult