Table of ContentsView AllTable of ContentsSymptomsCausesDiagnosisTreatmentPrevention
Table of ContentsView All
View All
Table of Contents
Symptoms
Causes
Diagnosis
Treatment
Prevention
Macrocytosisoccurs when your red blood cells (RBCs) are larger than normal and not functioning as they should. Macrocytosis is also called megalocytosis or macrocythemia.
This article discusses the symptoms and causes of macrocytosis. It also looks at how this condition is diagnosed and treated.
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What Are the Symptoms of Macrocytosis?
Generally, macrocytosis is associated with anemia (macrocytic anemia), which is diminished RBC count. The condition causes a decrease in oxygen delivered to the body’s tissues. Usually, the symptoms are mild to moderate, but sometimes the effects can be severe.
Common symptoms of macrocytosis include:
These symptoms can wax and wane in severity, and they may linger for months or longer before you feel the need to see a healthcare provider.
For example, you might feel energetic when you wake up from sleeping but then become more tired than usual as the day goes on. Or you may have some days of feeling more worn out than others. And illnesses, such as the common cold, can make you especially tired when you have macrocytosis.
What Is Macrocytic Anemia?
Associated Symptoms
If you have these symptoms along with fatigue or other direct signs of macrocytosis, let your healthcare provider know so you can get the right diagnostic testing.
What Causes Macrocytosis?
There are several causes of macrocytosis. The most common cause is a deficiency in vitamin B12 and folate (vitamin B9). These two vitamins cannot be produced in the body and must come from your diet.
There are several potential causes of vitamin B12 deficiency, including:
Potential causes of folate deficiency include:
Other causes of macrocytosis include:
Pathophysiology
The red blood cells in the body can be large for several reasons. Without vitamin B12 and folate, RBCs remain in an immature stage of development, which is larger than their mature size.
How Is Macrocytosis Diagnosed?
Macrocytosis is generally detected with a complete blood count test, which may be ordered to evaluate symptoms or as a routine screening. If you are found to have enlarged RBCs, you may also need to have diagnostic tests to determine the cause.
Generally, macrocytosis results from anemia, but macrocytosis without anemia also can occur. Either way, you may need the same diagnostic tests to determine the cause.
Blood measurements that can identify macrocytosis include the following, which are commonly reported as part of the complete blood count (CBC):
Red Blood Cell Count: Understanding MCV, MCH, RDW, and More
Depending on your other symptoms or medical conditions, your healthcare provider may order additional tests to identify the cause of your macrocytosis.These include looking at the white blood cell count, which is commonly part of the CBC.
Tests you might have:
How Is Macrocytosis Treated?
Your healthcare provider may prescribe another treatment if your macrocytosis has a different cause.
Vitamin B12 Deficiency: Symptoms, Causes, Risks
Preventing macrocytosis generally involves making sure you get adequate nutrients in your diet. Having regular medical checkups is important as well. Your healthcare provider may detect early signs of the condition and initiate treatment before it begins to affect your quality of life.
If you have a medical condition that could predispose you to macrocytosis, it’s especially important that you have regular medical evaluations so that problems such as macrocytosis can be identified and treated at early stages.
Summary
Macrocytosis means that your red blood cells are larger than normal. It is associated with anemia, when you also have insufficient numbers of properly functioning red blood cells.
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Chiang CP, Wu YH, Chang JY, Wang YP, Wu YC, Sun A.Hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in atrophic glossitis patients with macrocytosis.J Formos Med Assoc. 2019;118(11):1515-1521. doi:10.1016/j.jfma.2019.07.001Pawlak R.Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians?Am J Prev Med.2015;48(6):e11-26. doi:10.1016/j.amepre.2015.02.009Toprak B, Yalcın HZ, Colak A.Vitamin B12 and folate deficiency: should we use a different cutoff value for hematologic disorders?Int J Lab Hematol.2014;36(4):409-14. doi:10.1111/ijlh.12158Johns Hopkins Medicine.Folate-deficiency anemia.Nagao T, Hirokawa M.Diagnosis and treatment of macrocytic anemias in adults.J Gen Fam Med.2017;18(5):200-204. doi:10.1002/jgf2.31Cakmakli HF, Torres RJ, Menendez A, et al.Macrocytic anemia in Lesch-Nyhan disease and its variants.Genet Med.2019;21(2):353-360. doi:10.1038/s41436-018-0053-1
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Chiang CP, Wu YH, Chang JY, Wang YP, Wu YC, Sun A.Hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in atrophic glossitis patients with macrocytosis.J Formos Med Assoc. 2019;118(11):1515-1521. doi:10.1016/j.jfma.2019.07.001Pawlak R.Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians?Am J Prev Med.2015;48(6):e11-26. doi:10.1016/j.amepre.2015.02.009Toprak B, Yalcın HZ, Colak A.Vitamin B12 and folate deficiency: should we use a different cutoff value for hematologic disorders?Int J Lab Hematol.2014;36(4):409-14. doi:10.1111/ijlh.12158Johns Hopkins Medicine.Folate-deficiency anemia.Nagao T, Hirokawa M.Diagnosis and treatment of macrocytic anemias in adults.J Gen Fam Med.2017;18(5):200-204. doi:10.1002/jgf2.31Cakmakli HF, Torres RJ, Menendez A, et al.Macrocytic anemia in Lesch-Nyhan disease and its variants.Genet Med.2019;21(2):353-360. doi:10.1038/s41436-018-0053-1
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Chiang CP, Wu YH, Chang JY, Wang YP, Wu YC, Sun A.Hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in atrophic glossitis patients with macrocytosis.J Formos Med Assoc. 2019;118(11):1515-1521. doi:10.1016/j.jfma.2019.07.001Pawlak R.Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians?Am J Prev Med.2015;48(6):e11-26. doi:10.1016/j.amepre.2015.02.009Toprak B, Yalcın HZ, Colak A.Vitamin B12 and folate deficiency: should we use a different cutoff value for hematologic disorders?Int J Lab Hematol.2014;36(4):409-14. doi:10.1111/ijlh.12158Johns Hopkins Medicine.Folate-deficiency anemia.Nagao T, Hirokawa M.Diagnosis and treatment of macrocytic anemias in adults.J Gen Fam Med.2017;18(5):200-204. doi:10.1002/jgf2.31Cakmakli HF, Torres RJ, Menendez A, et al.Macrocytic anemia in Lesch-Nyhan disease and its variants.Genet Med.2019;21(2):353-360. doi:10.1038/s41436-018-0053-1
Chiang CP, Wu YH, Chang JY, Wang YP, Wu YC, Sun A.Hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in atrophic glossitis patients with macrocytosis.J Formos Med Assoc. 2019;118(11):1515-1521. doi:10.1016/j.jfma.2019.07.001
Pawlak R.Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians?Am J Prev Med.2015;48(6):e11-26. doi:10.1016/j.amepre.2015.02.009
Toprak B, Yalcın HZ, Colak A.Vitamin B12 and folate deficiency: should we use a different cutoff value for hematologic disorders?Int J Lab Hematol.2014;36(4):409-14. doi:10.1111/ijlh.12158
Johns Hopkins Medicine.Folate-deficiency anemia.
Nagao T, Hirokawa M.Diagnosis and treatment of macrocytic anemias in adults.J Gen Fam Med.2017;18(5):200-204. doi:10.1002/jgf2.31
Cakmakli HF, Torres RJ, Menendez A, et al.Macrocytic anemia in Lesch-Nyhan disease and its variants.Genet Med.2019;21(2):353-360. doi:10.1038/s41436-018-0053-1
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