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Hematocrit Test

⚠️ Update approaching🔬 Evidence: ModerateHematology
Diğer adları: Haematocrit, Hct, Packed cell volume
⚠️

Discuss your test results with your doctor. This page is for informational purposes only and does not provide a diagnosis.

⚡ Key Facts

• Measures the percentage of blood volume occupied by red blood cells • Men: 40–54% | Women: 36–48% • Closely parallels hemoglobin — both assess oxygen-carrying capacity • Affected by hydration status

🧪 What Does This Test Measure?

The hematocrit test measures the percentage of blood volume occupied by red blood cells, closely paralleling hemoglobin as an indicator of oxygen-carrying capacity.

📋 Why Is It Ordered?

Ordered for anemia and polycythemia evaluation, fluid balance monitoring, preoperative assessment, and general health screening.

🔧 Preparation

Part of the CBC. No special preparation is required.

📊 Reference Ranges

Men: 40–54% Women: 36–48% Pregnant women: physiological decrease in the second trimester ⚠️ Reference ranges vary by laboratory.

⬆️ High Values

Elevated hematocrit may be associated with dehydration, chronic lung disease, high altitude, smoking, or polycythemia vera.

⬇️ Low Values

Low hematocrit may be associated with anemia, fluid overload, acute bleeding, or physiological dilution during pregnancy.

⚙️ What Can Affect Results?

Dehydration, fluid overload, tourniquet duration, body position, pregnancy, altitude, and smoking may affect hematocrit results.

🔬 Evidence Summary

Moderate evidence: 1 guideline and 4 reviews/observational studies.

📚 Most Important Studies on This Topic

1

Guideline on haemoglobin cutoffs to define anaemia in individuals and populations

Guideline· World Health Organization · 2024 · PMID: 38530913

2

Investigation and management of erythrocytosis

Review· CMAJ · 2020 · PMID: 32778603

3

Haemoglobin thresholds to define anaemia from age 6 months to 65 years: estimates from international data sources

Observational· Lancet Haematology · 2024 · PMID: 38432242

✅ Key Takeaways

💡

What you learned: Hematocrit reflects the red blood cell proportion in blood. It closely parallels hemoglobin and is affected by hydration status.

⛔

A hematocrit result alone cannot diagnose anemia or polycythemia. Hemoglobin, clinical context, and additional tests are needed.

🔬 Sources Used on This Page

5 sources · Most recent publication: 2024
📋
Guideline
Expert society and guideline recommendations
1
source
📖
Review
Comprehensive topic evaluation
3
sources
👁
Observational
Observational and cohort studies
1
source
Overall assessment: Evidence level for this topic is moderate. This page is supported by 1 guideline, 3 reviews, 1 observational study.

📝 Questions to Ask Your Doctor

Be prepared for your appointment. Add questions to your list.

📋 References

[PMID: 38530913] Guideline on haemoglobin cutoffs to define anaemia in individuals and populations. World Health Organization, 2024.
[PMID: 38432242] Haemoglobin thresholds to define anaemia from age 6 months to 65 years: estimates from international data sources. Lancet Haematology, 2024.
[PMID: 32778603] Investigation and management of erythrocytosis. CMAJ, 2020.
[PMID: 27195903] Laboratory diagnosis of anemia: are the old and new red cell parameters useful in classification and treatment, how?. International Journal of Laboratory Hematology, 2016.
[PMID: 25946282] Iron-deficiency anemia. N Engl J Med, 2015.
Last reviewed: 4/2/2026
Next review: 4/2/2027

⚖️ Comparisons

Hemoglobin vs Hematocrit→

🔗 Related Topics

🧪 Hemoglobin (paralel parametre)🧪 Hemogram (tam kan sayımı)🧪 MCV (ortalama eritrosit hacmi)🧪 Ferritin (demir depoları)
⚖️ This page does not replace medical advice. Make treatment decisions with your doctor.
Content is based on scientific studies indexed in PubMed and current clinical guidelines.