Test: Red Blood Cells (RBC) Count

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Background/Purpose

Erythrocytes or red blood cells (RBCs) are the cells in the circulation that carry oxygen to and remove carbon dioxide from the tissues throughout the body. They are produced in the bone marrow in response to erythropoietin where they transition through six stages over a seven day period. When they are released into the circulation, their nucleus has been extruded and they measure 6-8 microns in diameter. The lifespan of RBCs is about 120 days. When the RBC ages the cell membrane becomes less pliable and tears as they cell travels through the micro vessels of the body. The damaged RBCs are removed from the circulation by the spleen. Variations in number, shape and size of RBCs are indicative of many diseases and disorders. There are many factors that may lead to decreased numbers of RBCs including hemorrhage, hemolysis, iron or vitamin deficiency, marrow failure and more. Larger than normal RBCs may be indicative of liver disease while smaller than normal RBCs are seen in thalassemias and other anemias.(Mosby's manual of diagnostic and laboratory tests, Kathleen Deska Pagana; Timothy James Pagana, Elsevier St. Louis, Mo ©2010)

Procedure

A blood draw is made from the patient.
Specimen: Whole blood
Volume: Fill tube to capacity.
Minimum Volume: 0.5 mL (500 μL for pediatric microtainer capillary tubes; fill tube to capacity)
Container: Lavender-top (EDTA) tube
Collection: Invert tube 8 to 10 times immediately after tube is filled at the time of collection.
Storage Instructions: Maintain specimen at room temperature.
Performed: Bilaterally

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RBC Count

Criteria

• Normal number of RBCs
• Normal type of RBCs

Measurement

x10^6/uL

LOINC Code

789-8

Scale/Grading

selection range; grade - LOINC ID
Option - Value option selection range; grade - LOINC IDNormal between 3.77-5.28 x10^6/uL ; Pass - Low < 3.77 x10^6/uL ; Fail - High > 5.28 x10^6/uL ; Fail -