What is hematocrit (Hct)?

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Last updated: March 28, 2025View editorial policy

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From the Guidelines

Hematocrit (Hct) is a measure of the percentage of red blood cells in the blood, with a target range of 33% to 36% for patients undergoing Epoetin therapy, as recommended by the NKF-K/DOQI clinical practice guidelines 1.

Definition and Purpose

Hematocrit is a blood test that measures the proportion of blood volume made up of red blood cells. It is an essential component of a complete blood count (CBC) and helps doctors assess overall health and detect conditions such as anemia or polycythemia.

Normal Ranges

Normal hematocrit ranges vary by gender, with adult men typically having a range of 38.3% to 48.6% and adult women having a range of 35.5% to 44.9%. However, these ranges may not be applicable to all individuals, particularly those with chronic kidney disease (CKD) or other medical conditions.

Factors Affecting Hematocrit

Several factors can influence hematocrit values, including:

  • Dehydration
  • Pregnancy
  • Living at high altitudes
  • Certain medications
  • Medical conditions affecting red blood cell production or destruction

Measurement and Monitoring

Hematocrit can be measured using automated cell counters, which provide more accurate and standardized results compared to manual methods. However, hemoglobin (Hgb) is considered a more accurate measure of anemia than hematocrit, particularly in patients with CKD, due to its stability and reduced variability across automated analyzers 1.

Clinical Significance

Hematocrit values have significant implications for patient outcomes, particularly in patients with CKD. A hematocrit below 30% has been associated with increased mortality, left ventricular hypertrophy, and decreased quality of life 1. In contrast, maintaining a hematocrit within the target range of 33% to 36% has been shown to improve survival, reduce the risk of cardiovascular events, and enhance quality of life. Therefore, it is essential to monitor and manage hematocrit levels carefully in patients with CKD, using evidence-based guidelines and accurate measurement methods 1.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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