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Hematocrit

Hematology Unit: %

Volume percentage of RBCs in blood

Also known as: Hct,Haematocrit,PCV,Packed Cell Volume,Packed Cell Volume (PCV)

Reference Ranges

Clinical Reference 36.0 – 50.0 %
Optimal Range 40.0 – 48.0 %
Critical Range < 21.0 / > 60.0 %

Men: 41-50%; Women: 36-46%

Related Conditions

Polycythemia High
Chronic Hypoxia High
Dehydration High
Anemia Low
Iron Deficiency Anemia Low
Chronic Disease Anemia Low
Internal Bleeding Low

Food & Lifestyle Recommendations

🍎 Food Eat iron-rich foods: red meat, liver, lentils, spinach, and fortified cereals Heme iron from animal sources has 2-3x better absorption than non-heme iron
🍎 Food Pair iron-rich foods with vitamin C sources (citrus, bell peppers) to enhance absorption Vitamin C increases non-heme iron absorption by 2-6x in clinical studies
🍎 Food Avoid coffee and tea with iron-rich meals — tannins inhibit iron absorption Tannins can reduce iron absorption by 20-60% when consumed with meals
🍎 Food Stay well-hydrated — dehydration can falsely elevate hematocrit Plasma volume contraction from dehydration concentrates cellular elements
🏃 Exercise Moderate exercise supports healthy RBC production, but avoid overtraining Strenuous endurance exercise can cause exercise-induced anemia via hemolysis
🏃 Exercise Regular moderate exercise supports cardiovascular health Adequate hydration before and after exercise helps maintain blood volume

Evidence-Backed Supplements

When High

When Low

  • Iron Tier A May Increase

    Strong evidence; iron deficiency is the leading cause of low hematocrit. Meta-analyses confirm iron supplementation raises Hct in deficient populations.

    Iron bisglycinate or ferrous fumarate 25–65 mg elemental iron/day On empty stomach or with vitamin C
    PMID 40159279 PMID 30699468 PMID 24990381
  • Vitamin B12 Tier A May Increase

    Well-established; B12 deficiency causes macrocytic anemia with low hematocrit. Supplementation corrects deficiency-induced anemia.

    Methylcobalamin or cyanocobalamin 1000–5000 mcg/day (sublingual preferred) Morning
    PMID 40147066 PMID 30431328 PMID 29543316
  • Folate Tier A May Increase

    Well-established; folate deficiency leads to megaloblastic anemia. Supplementation restores hematocrit in deficient individuals.

    Methylfolate (5-MTHF) 400–1000 mcg/day Morning
    PMID 28816346 PMID 25803792 PMID 32770489
  • Vitamin C Tier A May Increase

    Moderate evidence; vitamin C enhances non-heme iron absorption. Co-supplementation with iron improves hematocrit more than iron alone.

    Ascorbic acid or liposomal vitamin C 500–2000 mg/day Divided doses
    PMID 26415762 PMID 28301692 PMID 23440782

Questions to Ask Your Doctor

  • Should I be tested for iron deficiency or internal bleeding as a cause of my low hematocrit? Low hematocrit warrants investigation for iron deficiency, B12/folate deficiency, or occult bleeding.
  • Could my low hematocrit be related to my medications or diet? Certain medications (NSAIDs, anticoagulants) and dietary insufficiency can lower hematocrit.
  • Could my high hematocrit indicate polycythemia or chronic hypoxia? Elevated hematocrit may indicate polycythemia vera, chronic hypoxia, or dehydration.

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