page header

Contents  ·  Introduction  ·  Learning  Objectives  ·  Textbook  ·  Lectures  ·  Procedures  ·  Final Exam  ·  Library  ·  Laboratory  ·  Pharmacy  ·  Imaging  ·  Forms  ·  Videos  ·  About  ·  Contact Us>

Hematocrit (Hct)

The hematocrit is a measure of the red blood cell mass, expressed as a percentage.

Blood is placed in a test tube and centrifuged to separate the heavier red blood cells from the lighter serum and plasma. The percentage of the blood volume occupied by the mass of red cells is the hematocrit.

Increased in the Presence of:

  • Hemoconcentration
  • COPD (chronic obstructive pulmonary disease)
  • CHF (congestive heart failure)
  • Smokers
  • Pre-eclampsia

Decreased in the Presence of:

  • Anemia
  • Leukemia
  • Hyperthryroidism
  • Chronic liver disease
  • Hemolysis:
    • Transfusion reaction
    • Drug/chemical reaction
    • Infection
    • Burns
    • Mechanical disruption (artificial heart valves)
  • Systemic Disease
    • Cancer
    • Lupus
    • Sardoidosis

Special Considerations

  • Smokers typically have elevated hematocrits in response to chronic, low-grade carbon monoxide poisoning and other mild respiratory ailments. Because of the carbon monoxide binding, they may still be functionally anemic, even though their hematocrit levels look good.
  • Adaptation to high altitudes includes moderate elevation of hematocrit.
  • During the initial phases of an acute hemorrhage, the hematocrit generally doesn't change very much. Later, as extracellular fluid is mobilized and IV fluids are incorporated, there is a dilutional effect that will lead to a reduced hematocrit. This fall in hematocrit may take several hours to develop.

Normal Values*

  Packed Cell Volume

Men

40%-54%
Women 37%-47%
Pregnancy 33%-44%
Newborn 50%-62%

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.

 

Source: Operational Medicine 2001,  Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300

Military Obstetrics & Gynecology
© 2003, 2004, 2005, 2006 Medical Education Division, Brookside Associates, Ltd.
All rights reserved

 


This information is provided by The Brookside Associates.  The Brookside Associates, LLC. is a private organization, not affiliated with any governmental agency. The opinions presented here are those of the author and do not necessarily represent the opinions of the Brookside Associates or the Department of Defense. The presence of any advertising on these pages does not constitute an endorsement of that product or service by either the US Department of Defense or the Brookside Associates. All material presented here is unclassified.

C. 2009, 2014, All Rights Reserved

brookside associates logo

 

 

 

 

 

 

Advertise on this site