Research Blog

August 25, 2023

CBC Biomarkers: Red Blood Cell (RBC) Count

Optimal Takeaways

Red blood cells (RBCs) are produced in the bone marrow and are abundant in circulation. They are vital to delivering oxygen to cells and tissues. They are also instrumental in picking up carbon dioxide and returning it to the lungs to be expelled. Red blood cells can be depleted or destroyed, causing anemia, compromising tissue oxygenation, and increasing the risk of CVD and mortality.

Low RBC counts are associated with anemia, bone marrow failure, nutrient deficiencies, and chronic illness, while levels can increase with dehydration, high altitude, and pulmonary disorders.

Standard Range:

Male 4.2 - 5.8 m/cumm    

Female 3.8 - 5.1 m/cumm    

The ODX Range:                 

Male 4.8 – 5.5 m/cumm

Female 4.3 – 4.8 m/cumm

Low RBC counts are associated with various types of anemia; bone marrow failure; reduced production due to pathology, renal disease, or nutrition deficiencies; leukemia and lymphoma; chronic illness; rheumatoid disease; increased RBC destruction; blood loss; pregnancy; and overhydration (Pagana 2021). Anemia is a risk factor for mortality or increased disease severity in chronic kidney disease, heart failure, ischemic heart disease, myocardial infarction, arrhythmias, and stroke (Anderson 2007).

High RBC counts may be associated with dehydration, increased oxygen-carrying requirements, including high altitudes; pulmonary fibrosis; COPD; chronic hypoxia; congenital heart disease; and polycythemia vera (Pagana 2021).


Red blood cells, called erythrocytes, are the most abundant cells in circulation. They differ fundamentally from other cells, lacking a nucleus, ribosomes, mitochondria, and other organelles (Pretini 2019). Their primary function is to carry oxygen from the lungs to peripheral tissues and then carry carbon dioxide back to the lungs, where it can be expelled. Production of RBCs is called erythropoiesis, a process controlled by the hormone erythropoietin produced in the kidney (Pagana 2021).

A reduction in RBC count or hemoglobin content can lead to anemia, as can nutrient insufficiencies that cause alterations in red blood cell shape and size. Anemia can also occur with RBC destruction, blood loss, inflammation, infection, and chronic disease (Da Silva 2021).

RBCs communicate with various cells, including platelets, endothelial cells, macrophages, and even bacteria. Pathological conditions such as sickle cell disease, polycythemia vera, diabetes, and malaria can cause RBC morphology and function changes, increasing their adhesion to each other and the vascular endothelium (Pretini 2019).

Red blood cells can be destroyed due to an enlarged spleen (e.g., leukemia or portal hypertension) or intravascular RBC trauma, including atherosclerotic plaque (Pagana 2021). Oxidative stress can damage RBCs and contribute to anemia. Antioxidants such as vitamins C and E can reduce that damage and improve RBC integrity (TJ 2018).

In one general population study of 114,496 adults, mortality was highest in men, with the lowest RBC counts of 4.49 m/cumm in quartile 1 versus 5.44 in quartile 4, especially when hemoglobin dropped below 14 g/dL (140 g/L). The death rate in women was greater, with an RBC of 3.95 versus the highest RBC at 4.76 m/cumm (Kim 2012).

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Anderson, Jeffrey L et al. “Usefulness of a complete blood count-derived risk score to predict incident mortality in patients with suspected cardiovascular disease.” The American journal of cardiology vol. 99,2 (2007): 169-74. doi:10.1016/j.amjcard.2006.08.015

da Silva Lopes, Katharina et al. “Nutrition-specific interventions for preventing and controlling anaemia throughout the life cycle: an Overview of systematic reviews.” The Cochrane database of systematic reviews vol. 9,9 CD013092. 26 Sep. 2021, doi:10.1002/14651858.CD013092.pub2

Hatamian, Hamidreza et al. “The relationship between stroke mortality and red blood cell parameters.” Iranian journal of neurology vol. 13,4 (2014): 237-40.  

Kim, Yong Chul et al. “The low number of red blood cells is an important risk factor for all-cause mortality in the general population.” The Tohoku journal of experimental medicine vol. 227,2 (2012): 149-59. doi:10.1620/tjem.227.149  

Pagana, Kathleen Deska, et al. Mosby's Diagnostic and Laboratory Test Reference. 15th ed., Mosby, 2021.

Pretini, Virginia et al. “Red Blood Cells: Chasing Interactions.” Frontiers in physiology vol. 10 945. 31 Jul. 2019, doi:10.3389/fphys.2019.00945

TJ, Ainsy Goldlin. "Efficacy of Vitamin C and Vitamin E as an add on therapy in diabetic foot ulcer and red blood cell morphology as a biomarker of oxidative stress: a randomized, open label, comparative pilot study." (2018).

Tag(s): Biomarkers

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