Wentworth-Douglass Hospital
(603) 742-5252
Decrease (-) Restore Default Increase (+) font size
Physicians
Ebola: what you should know
Health Library
Back to Health Library   Print This Page Print    Email to a Friend Email

Blood test
Blood test


Formed elements of blood
Formed elements of blood


High blood pressure tests
High blood pressure tests


Definition:

An RBC count is a blood test that tells how many red blood cells (RBCs) you have.

RBCs contain hemoglobin , which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work.



Alternative Names:

Erythrocyte count; Red blood cell count



How the test is performed:

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.



How to prepare for the test:

No special preparation is necessary for adults.



How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.



Why the test is performed:

The RBC count is almost always part of the CBC (complete blood count) test.

The test can help diagnose anemia and other conditions affecting red blood cells.

Additional conditions under which an RBC count may be performed:



Normal Values:

Normal results vary, but in general the range is as follows:

  • Male: 4.7 to 6.1 million cells per microliter (cells/mcL)
  • Female: 4.2 to 5.4 million cells/mcL


What abnormal results mean:

Higher-than-normal numbers of RBCs may be due to:

Your RBC count will increase for several weeks when you move to a higher altitude.

Drugs that can increase the RBC count include:

  • Gentamicin
  • Methyldopa

Lower-than-normal numbers of RBCs may be due to:

  • Anemia
  • Bone marrow failure (for example, from radiation, toxins, or tumor)
  • Erythropoietin deficiency (secondary to kidney disease )
  • Hemolysis (RBC destruction) due to transfusion, blood vessel injury, or other cause
  • Hemorrhage (bleeding)
  • Leukemia
  • Malnutrition
  • Multiple myeloma
  • Nutritional deficiencies of:
  • Overhydration
  • Pregnancy

Drugs that can decrease the RBC count include:

  • Chloramphenicol
  • Hydantoins
  • Quinidine


What the risks are:

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)


References:

Zuckerman K. Approach to the anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 162.




Review Date: 3/2/2009
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com


Find What You Need

Events
Careers
Foundation
About Us
Contact
Directions
News
Social Media Agreement
Joint Notice
Web Privacy Policy
WDH Staff Portal

Centers & Services

Cancer Center
Cardiovascular Care
Joint Replacement
Women & Children's
Physician Offices
Other Services

Conditions & Treatments

Health Library

Support Services

Support Groups
Care-Van
Dental Center
Social Work
Food & Nutrition
Integrative Wellness
Spiritual Care
Concerns & Grievances
Homecare and Hospice

For Patients

Pay Your Bill Online
Pricing Estimates
Financial Assistance
Interpreter Services
Surgery Preparation
Medical Record Request
Advance Directives
Clinical Research & Trials

For Healthcare Professionals

Work and Life
Financial Well-Being
Career and Growth

The Wentworth-Douglass Health System includes:

 

Address

Wentworth-Douglass Hospital
789 Central Avenue, Dover, NH 03820
Phone: (603) 742-5252
Toll free: 1 (877) 201-7100