00:00Most of us are not familiar with the MCV, so receiving a report telling us our MCV is high may
00:07arouse our curiosity.
00:09This can get even more concerning if your doctor tells you he needs you to run some more tests.
00:16That by itself would tell us that there's some significance to this finding.
00:22So is a high MCV something you should worry about?
00:26Well, usually there's no reason to panic, but it is worth finding out why it is high because the causes
00:35of an elevated MCV range from something as correctable as a vitamin deficiency to, much less commonly, a disorder of
00:45the bone marrow itself.
00:47By a high MCV, we mean an MCV that is greater than 100 femtiliters.
00:53Normally, the MCV is 80 to 100 fL.
00:58MCV stands for mean corpuscular volume.
01:01It tells us the average size or volume of your red blood cell.
01:05So an MCV of less than 80 means the red blood cell is smaller than normal.
01:11And an MCV greater than 100 means that your red blood cells, on average, are larger than normal.
01:19Putting your red blood cells into categories like this can help doctors with diagnosing diseases.
01:27That is because the MCV varies with different types of diseases.
01:33But remember, you can have an MCV without actually being anemic.
01:39When it comes to anemias, the MCV can guide doctors into finding the particular type of anemia.
01:48Doctors often use MCV to classify anemia into three groups.
01:54Small red blood cells are called microcytic.
01:58Normal size cells, normocytic.
02:01Large blood cells, macrocytic.
02:04That's a useful classification because each group tends to have a different set of causes.
02:10So when your MCV is high, it immediately gives your doctor some clues about where to look next.
02:18Now for simplicity, we can group many of the common causes of a high MCV into five broad categories.
02:26Number one, B12 or folate deficiency.
02:30Number two, alcohol or meditations.
02:34Number three, liver or thyroid diseases.
02:37Number four, bone marrow is releasing too many young red blood cells.
02:43Number five, which is the least common, a bone marrow disorder itself.
02:49Vitamin B12 and folate deficiencies are two important and treatable causes.
02:54But they are not the only ones.
02:57Your doctor will run tests in your blood to measure the levels of your B12 and folate.
03:03If B12 or folate is low, the deficiency can be treated.
03:09Your doctor may also need to determine why the vitamin level became low in the first place.
03:15Your doctor may also look at your blood under a microscope and check something called the reticulocyte count.
03:21The microscopic test, called the peripheral smear, lets your doctor actually look at the size and appearance of the blood
03:30cells under a microscope.
03:33That can provide clues about whether a vitamin deficiency or another problem is affecting the cells being produced in the
03:44bone marrow.
03:44The reticulocyte count measures young red blood cells.
03:50If that number is high, it can suggest that your body is replacing red blood cells that have been lost
03:58through bleeding or being destroyed prematurely.
04:01Your doctor will also review your medications.
04:06Drugs such as methotrexate and several other medications can affect red blood cell development.
04:14Depending on why you're taking those medications and how significant the abnormality is,
04:21your doctor may adjust the treatment or investigate further.
04:25Alcohol is another common reason for an elevated MCV.
04:32It can enlarge red blood cells even when folate levels are normal,
04:38although people who drink heavily may also develop folate deficiency.
04:45If alcohol appears to be contributing, your doctor will discuss reducing or stopping alcohol safely.
04:54For the third category, your doctor will look at your liver and your thyroid function tests.
05:03If there are any abnormalities, he will treat those.
05:08The fourth category is more complex.
05:13This is because young red blood cells, called reticulocytes, are larger than mature red blood cells.
05:21So, if your bone marrow suddenly starts making lots of new red blood cells,
05:28for example, after bleeding or when red blood cells are being destroyed,
05:34the MCV can rise.
05:38The fifth category involves diseases of the bone marrow itself that require a closer look.
05:45If the MCV remains unexplained, particularly if other blood counts and are abnormal
05:55or the blood smear shows concerning changes,
05:59your doctor may refer you to a hematologist.
06:04In some cases, a bone marrow biopsy may then be necessary.
06:09So, let's review the numbers.
06:13An MCV above 100 is considered high,
06:17although the exact range may vary slightly from laboratory to laboratory.
06:23A high MCV does not automatically mean that something serious is wrong.
06:29Common causes include vitamin B12 or folate deficiency,
06:35alcohol, medications, liver diseases, and thyroid diseases.
06:42Sometimes, it happens because your body is rapidly producing new red blood cells.
06:48And less commonly, it can point towards a disorder of the bone marrow.
06:54So, don't panic over one high MCV result, but don't ignore it either.
07:02The MCV is a clue.
07:05The important question is, what is causing it?
07:10I hope you found this video useful.
07:12If you did, like and share the video with your friends and family.
07:16You can support this channel by subscribing.
07:19Until the next video, stay healthy and stay safe.
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