- With Mayo Clinic hematologist
Ruben Mesa, M.D.
read biographyclose windowBiography of
Ruben Mesa, M.D.
Ruben A. Mesa, M.D.
Ruben A. Mesa, M.D., is board certified in internal medicine, hematology and medical oncology and is a consultant and section head in the Division of Hematology and Internal Medicine at Mayo Clinic, Rochester, Minn., and an associate professor of medicine at Mayo Medical School.
The Chicago-area native's primary field of interest is hematology with special interests in both acute and chronic leukemias — specifically the chronic myeloproliferative disorders (MPDs).
"I believe patients' understanding of their disease is a critical first step in the healing process," he says. "I believe that the Internet, carefully used, is a phenomenal resource for patients to be able to access high-quality and valuable information to understand both their diseases and various treatments."
Dr. Mesa has been with Mayo Clinic throughout his training since 1991 and is a graduate of Mayo Medical School. He is a member of the American Society of Hematology, the American Society of Clinical Oncology and the American College of Physicians.
His scholarship has focused on advancing the understanding and therapy of the chronic myeloproliferative disorders. In these disorders, he has been active in evaluating novel therapeutics, implementing clinical trials, working with quality of life studies, and actively involved with national patient groups.
He is supported in these efforts by research funding from the National Cancer Institute, the MPD Foundation, and Mayo Clinic's Hematologic Malignancy Program. He is principal investigator in several trials specifically for myelofibrosis, and is organizing a trial using exercise to counteract MPD-associated fatigue. He is committed to improving the therapy and quality of life in MPD patients. He has lectured both nationally and internationally on these disorders.
Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get Started
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Question
Macrocytosis: What causes it?
What causes enlarged red blood cells (macrocytosis)?
Answer
from Ruben Mesa, M.D.
Macrocytosis is a term used to describe red blood cells that are larger than normal. It typically causes no symptoms and is usually detected incidentally on routine blood tests.
Macrocytosis isn't a specific disease but may indicate an underlying problem that requires medical evaluation. Common causes of macrocytosis include:
- Vitamin B-12 deficiency
- Folate deficiency
- Liver disease
- Alcoholism
- A side effect of certain medications, such as chemotherapy drugs
- Increased red blood cell production by the bone marrow (regeneration) to correct anemia, for example, after blood loss
If you have macrocytosis, blood tests can help determine its cause. In some cases, it may be necessary to remove a sample of your bone marrow — the spongy tissue inside your bones — for testing (bone marrow biopsy and aspiration).
Treatment of macrocytosis is directed at the underlying cause. In the case of vitamin B-12 or folate deficiency, for instance, treatment may include diet modification and dietary supplements or injections. If macrocytosis is caused by severe anemia, a blood transfusion might be necessary.
