Macrocytic Anemia is a 
Sign that Something is Wrong!

Macrocytic Anemia, also called Macrocytosis, is a condition of larger, oddly shaped and fewer red blood cells that occurs for a variety of reasons. Primarily this shows up on a blood test by a high number on the MCV Blood Test that is a portion of the Complete Blood Count- or CBC test- which is part of most routine blood tests.

The condition gets its name from how it appears on the blood test. The word 'Macro' means large, as in a 'macro' lens on a camera. The prefix 'cy' or 'cyto' means cell and the word 'anemia' refers to any condition of fewer red blood cells or hemoglobin.

Hence the word Macrocytic Anemia or macrocytosis. Macrocytic anemia is most often caused by an individual problem or a combination of problems such as:



  • Vitamin B12 Deficiency
  • Alcoholism
  • Folic Acid Deficiency
  • Vitamin B6 Deficiency
  • MTHFR Gene Mutation
  • Malabsorption Problems such as Gluten Sensitivity
  • or drug side effects such as:

  • Side Effects of Metformin
  • Nitrous Oxide Side Effects
  • Acid Reflux Medication
  • But regardless, a high MCV should prompt further investigation by your doctor into WHY you have this problem. However, it's VERY often the case that a high MCV blood test gets overlooked as not being significant- when it can be EXTREMELY significant to your health. In fact, when you begin Understanding Blood Test Results, you'll see that the finding of Macrocytosis can indicate serious conditions that have been causing your health problems for YEARS and are only now showing up on your blood test! If you have had chronic health conditions, macrocytic anemia could finally show what your problem has been all of this time.



    But ONLY if your doctor is vigilant about looking into the causes of macrocytic anemia and seeing it as the problem of serious nutritional deficiencies that it is- unfortunately, most doctors DON'T see it this way and don't understand about the serious health implications of the underlying causes of this important sign. So, what can this problem mean to you?

    Vitamin B12 Deficiency is the 
    Main Cause of Macrocytic Anemia

    Macrocytosis should ALWAYS make your doctor do further testing for Vitamin B12 deficiency. These enlarged blood cells are the 'Hallmark Sign' of Vitamin B12 deficiency and should NEVER be overlooked as such- especially in cases where you are experiencing fatigue.

    In fact, macrocytic anemia is a late sign of vitamin b12 deficiency that occurs only after vitamin b12 deficiency has occurred for over 2 years!! Unfortunately, there are two problems with your doctor doing further testing for Vitamin B12 Deficiency:

      First: As we mentioned before, doctors will often overlook mild macrocytosis as unimportant- even if you have had chronic health problems. And so you don't get testing for Vitamin B12 even if you have the 'Hallmark Sign' of it.

      Second: Even in cases where your doctor DOES follow through and test for b12 deficiency, the results of your Vitamin B 12 Levels should NOT be relied upon anyway!

    Macrocytosis Size Does Matter for RBC's on an MCV Test

    While a LOW Vitamin B12 level is accurate and will prompt your doctor to have you take Vitamin B12 Supplements, a NORMAL Vitamin B 12 Levels should NOT be trusted. A better strategy for those with macrocytosis is to do one of two things- especially if you have ANYdegree of fatigue:

    • Get a Methylmalonic Acid Test: A Methylmalonic Acid test is MUCH more accurate in determining the need for vitamin b12 levels. It can also be done on urine so it eliminates the need for another blood test  
    • Just Start Taking Vitamin B12: Because testing has many flaws and seems to miss SO many cases of vitamin b12 deficiency, it is safe and a much better indication of your need for vitamin B12 to simply follow the instructions on the Treatment of Vitamin B12 Deficiency page. If you feel better, then you have vitamin b12 deficiency and you also have a solution to it! Great! And you didn't have to go to doctor's visits, get lab tests, or spend thousands of dollars. Why doesn't everyone just try this? 

    So, if you have low vitamin b12 levels OR you feel better on vitamin b12, now you need to determine WHY you have low vitamin b12. Low vitamin b12 levels are NOT normal and- if you are not an alcoholic or a vegan- usually indicate some sort of malabsorption problem. So, it's time for you to go read the Causes of B12 Deficiency page and figure out WHY why you are low.



    But why would you have Vitamin B12 Deficiency? There is a cause for this too, although doctors will generally 'just' diagnose it, give you pills or shots and send you on your way, this is wrong-headed. There is always a reason for Vitamin B12 Deficiency, and the Causes of Vitamin B12 Deficiency, such as MTHFR Gene Mutation, H Pylori Bacteria or Gluten Sensitivity. So don't stop until you find out WHY you have macrocytosis. If you do, you will be missing out on a major opportunity to finally get answers to your health problems...

    Keep reading to find out more about the Causes of Vitamin B12 Deficiency.

    Next --->
    Causes of Vitamin B12 Deficiency 

    Already Answered Questions about this Laboratory Test

    Click below to see already answered questions about this laboratory test

    Low RBC and high MCV 
    My Complete Blood Count readings were all considered normal except for RBC of 3.79 and MCV of 104.5. I'm 81 go to the gym four to five days each week. …

    Dear doctor, thank you for helping me. My latest blood analysis were slightly out of range (see below). Should I be concern or is it due to the pregnancy? …

    High MCV Test and Feeling Tired 
    I had a CBC in March 2014 and cholesterol check July 2014. All my labs came back normal except the MCV was high. They said mine is 94.8 and range is …

    Vitamin B12 and MCV Levels 
    I have recently had bloods done as am experiencing extreme fatigue, loose bowels and headaches. Loose bowels been ongoing problem for years, as is the …

    Raised MCV Level of 103 
    I have been having a consistently raised mcv (103, I am female) for a couple of years. Nothing else is raised (tft,wcc b12 folates, lft are all normal) …

    I was diagnosed w/Macrocytosis 3yrs ago but my Dr.says there is nothing to do about it. 
    Could you help me understand my cbc? Tests: (1) CBC/Diff Ambiguous Default (977709) WBC 9.9 x10E3/uL 3.4-10.8 RBC 3.97 x10E6/uL …

    elevated mcv and mch with Vitamin B12 elevated 
    I had blood work as recent as July 2013 and going back past 5 years & my MCV & MCH has always been elevated. The srrange thing is my Vitamin B12 & Folic …

    Macrocytosis Prognosis 
    I was diagnosed with macrocytosis about 13 or 14 years ago. I didn't think, nor was I led to believe, that this was anything to worry about. However …

    I have a blood count of 108 
    Yesterday I went to the hospital to have checks done for a enlarged red blood cells. They said that I have been steadily increasing from 101 since 2005 …

    Does a Low MCV Mean that I Have Anemia? 
    My main symptom is tiredness the thing is that every time I go to the doctor they only tell me that I have hypoglycemic and to eat every 2 hours. But they …

    MCV Test is 103 
    my MCV is 103 but my B12 is 870. I take b12 due to gastic bypass I laso have RBC of 4.12 and RDW of 11 and MPV of 7 and WBC of 3.8 but my doctors say …

    Diagnosed with Macrocytosis 
    I have just been diagnosed with macrocytosis. My last blood test was in June of 2012 and all blood tests were normal. I have been on humira for one year …

    Chronically Elevated MCV 
    The past 3 blood tests I've had showed an elevated MCV. All were slightly over 100. My doctor tests me for vitamin B12 levels regularly and they are always …

    high hematocrit and high MCV 
    I am a 53 year old female I just received blood test results. My Hematocrit level was 44.8 and my MCV level was 99. test says this is high should I be …

    Macrocytic Anemia and Vitamin D Deficiency 
    I have had macrocytic anemia for at least 10 years, enough that my dr. even did a bone marrow test. Now, at age 58 I have been diagnosed with osteopenia …

    Help for Persistent Macrocytic Anemia 
    I have had persistent macrocytosis since 1992. At one time, the MCV was 108, but it has now plateaued to 102. For several years, I have had problems with …

    Can't find reason for Macrocytosis! 
    I have been through my general practitioner, 2 hematologists and 2 stress tests to find the origin of my Macrocytic Anemia ! PLEASE HELP! I have been …

    Macrocytic or Pernicious Anemia 
    My blood tests results have been abnl: MCV 102.7 MCH 35.4 MPV 6.1 Low Protein, low albumin, unexplained wt. loss, GI probs Are finding indicative …

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