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So - I made an observation and am hoping someone could share some info on this. Hyperadrenergic POTS affects most females in my family. Recently I spent time with my sister and we found out that we both have large red blood cells. This means the red blood cell count is low but the cells are too large, therefore they can mimick low blood volume. In the CBC it shows high MCV and MCHC. We both had this - as well as anemia - since childhood. I have found great improvement from IV fluid therapy and wonder if this could be the reason - that it somehow has something to do with the large blood cells? I have read somewhere once in an article that abnormalities in CBC are a underlying cause so I find this very interesting. Any input????

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Not sure I have anything scientific to bring but it seems likely there's a connection?

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That’s very interesting! My CBCs are always super boring - the only thing abnormal about them is low ferritin, but I think a lot of people with POTS struggle to keep those levels up. My MCV and MCHC are normal, but my RDW is sometimes low (although I don’t think that has any clinical significance).

So yeah, pretty boring. I have no idea what my blood volume is though... Did you have yours tested? How?

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In the past, my CBC's and CMP is always within normal ranges. It's why they doctors I see don't know what to think. 

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Well, I don't know how high an MCV is what you're calling high but no, I don't think it has anything to do with POTS. It doesn't have anything to do with whole blood volume. Typically, a high MCV indicates megaloblastic anemia caused by b12 or folate deficiency, which shouldn't be consistent finding over years without having to be treated. Hematology is my specialty area fwiw.

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36 minutes ago, toomanyproblems said:

Well, I don't know how high an MCV is what you're calling high but no, I don't think it has anything to do with POTS. It doesn't have anything to do with whole blood volume. Typically, a high MCV indicates megaloblastic anemia caused by b12 or folate deficiency, which shouldn't be consistent finding over years without having to be treated. Hematology is my specialty area fwiw. 

My MCV is above 101. Not sure what my sisters is but she says hers is elevated also. I have been treated for low B12 for years with IM supplementation of Vit B12 and my recent check showed normal B12 levels, so that cannot be it. My Ferritin was low at 4 but with oral iron it came up to 21.  The fact that we both have this anomaly in our CBC nd we both have hyper-POTS makes me wonder if it could be related? 

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An MCV of 101 is above normal (normal 80-100). How long have you had this high an MCV? Is your hemoglobin normal? 

I've researched the heck out of POTS and would be particularly attuned to any possible hematology connection. I can't see how the high MCV and hyperPOTS could be related. 

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I have HyperPOTS and my MCV is high too. Also treated for pernicious anemia with oral B12 and MCV still elevated. 

Don't know how this is tied in, but your post caught my eye.

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@toomanyproblems - my MCV has always been high and I always had anemia. My mother used to make me drink beet juice as a child, it's supposed to be good for anemia. Yuck!! My ferritin lst year was 4 but is now up to 21 with iron supplements. @KiminOrlando - I am trying to find this article I read years ago about how the "thick blood" can cause vasoconstriction because it makes the brain think we are bleeding out, so it clamps down the blood vessels. Could be an explanation but I will keep looking for the article and post it for you. 

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5 hours ago, Pistol said:

@toomanyproblems - my MCV has always been high and I always had anemia. My mother used to make me drink beet juice as a child, it's supposed to be good for anemia. Yuck!! My ferritin lst year was 4 but is now up to 21 with iron supplements. @KiminOrlando - I am trying to find this article I read years ago about how the "thick blood" can cause vasoconstriction because it makes the brain think we are bleeding out, so it clamps down the blood vessels. Could be an explanation but I will keep looking for the article and post it for you. 

One of the possible underlying causes of POTS is thick blood or APS, I think it's called. Do you eat food higher in iron?

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Ya'll are going all over the place. I'll say this on lab values -- for most tests, lab normal range is calculated as the values from 95% of the population. This means you have a chance of having a slightly abnormal value in one out of every 20 different lab tests you have and still be normal. IDK if this will help people to not be so upset over slightly abnormal values but there it is. So the more different lab tests you have, the greater your chances of a slightly abnormal value for one of more of them. That's not to say you should ignore them, but most tests that indicate a disease process have more than one type of test, be it labs, x-rays, etc., to help put the picture together. So more corroborating tests *may* be needed.

 An interesting variation from this way of determining normals from 95% of the population is back in the day when I started working in the lab, the normal range for cholesterol was 150-300mg/dL. This was even before they could break it down into the various fractions like LDL and HDL. Around the mid 1970s it was determined that the normal values were too high for actual normal. And that a large percent of the population on the higher end actually had values that be a factor in causing heart disease. So normal cholesterol values were changed to 125-200mg/dL. 

Many values that fall outside the normal range, such as the low RDW mentioned here, are not significant. RDW stands for red cell distribution width. If it's high, it means the reds cells are of widely varying sizes and could indicate an anemia the body is trying to compensate for by releasing younger (and larger due to their maturation stage) red cells from the bone marrow in order to get enough red cells to carry oxygen. This is generally considered a good sign in anemia but is notable as abnormal. If the RDW is low, it just means the red cells sizes are closer together than in most people. It's generally considered not to signify anything significant in a non anemic person. On the other end, when the HDL test first came out and we were calculating the normal values for our test, normals were drawn from the lab personnel as well as other places. My HDL value was higher than 95% of the others, so it was thrown out. But a high HDL is good. So it can go both ways.    

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@toomanyproblems so, what is megaloblastic anemia and thrombocytopenia? Are these relevant or coincidental and not contributing to my current mess? Secondary erythroid hyperplasia? All of this came from a bone marrow biopsy they did years ago. I have refused another one because I don't think there has been a significant enough change in my health to warrant it. I have an autoimmune disease if that is relevant. IGG is 'highly' elevated whatever highly means.

One of my doctors said that the 'normal' ranges on many of these tests were established years ago when it was not common to include many women as test subjects. She also said 'normal' for men and women can be very different on some things like thyroid. What is your opinion on this?

This is where stuff gets too complex for me. 

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6 hours ago, KiminOrlando said:

@toomanyproblems so, what is megaloblastic anemia and thrombocytopenia? Are these relevant or coincidental and not contributing to my current mess? Secondary erythroid hyperplasia? All of this came from a bone marrow biopsy they did years ago. I have refused another one because I don't think there has been a significant enough change in my health to warrant it. I have an autoimmune disease if that is relevant. IGG is 'highly' elevated whatever highly means.

One of my doctors said that the 'normal' ranges on many of these tests were established years ago when it was not common to include many women as test subjects. She also said 'normal' for men and women can be very different on some things like thyroid. What is your opinion on this?

This is where stuff gets too complex for me. 

I have a procedure tomorrow morning and can't answer thoughtfully right now. I'll try to get back with you tomorrow.

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On 3/14/2019 at 3:49 PM, KiminOrlando said:

@toomanyproblems so, what is megaloblastic anemia and thrombocytopenia? Are these relevant or coincidental and not contributing to my current mess? Secondary erythroid hyperplasia? All of this came from a bone marrow biopsy they did years ago. I have refused another one because I don't think there has been a significant enough change in my health to warrant it. I have an autoimmune disease if that is relevant. IGG is 'highly' elevated whatever highly means.

Megaloblastic anemia is typically defined as B12 and/or folate deficiency. Low platelets (thrombocytopenia) may also be present. The reason the red cells are large is because there's a defect in DNA synthesis in rapidly dividing cells such as red cells that causes cell growth without division, resulting in abnormally large red cells. There are other abnormalities associated such as hyper-segmented neutrophils (that may actually be the first sign of a megaloblastic anemia) and red cell abnormalities such as Howell Jolly bodies (clusters of DNA in the red cells, caused by the cell cycle asynchrony, that are too numerous for the spleen to remove) and abnormal red cell shapes. Both of these are noted in a stained blood smear when viewed under the microscope.  There is also normally an increase of the enzyme LDH relased from cell destruction of the fragile abnormal red cell precursor (abnormal immature red cell) in the bone marrow.

In megaloblastic anemia, there are decreased red cells, but the Mean Corpuscular Hemoglobin (MCH) is increased because the red cells are so large (increased Mean Cell Volume- MCV) the amount of hemoglobin in each of these large cells is increased. The Mean Corpuscular Hemoglobin Concentration (MCHC) which is expressed as a percentage, in not normally affected.

This type of anemia is usually slow to develop and the findings, when limited to this type of anemia alone, are distinct from iron deficiency anemia. In the common iron deficiency anemia, findings are also low red cell counts but low MCV and MCH due to small red cells, and also often low MCHC because there is less hemoglobin in each of red cells percentage-wise.

Other things that can cause megaloblastic anemia are chemotherapy types of treatment such as methotrexate used for autoimmune conditions such as rheumatoid arthritis. These agents act to disrupt DNA synthesis and cause asynchrony of cell growth in the bone marrow in a similar way as B12 and folate deficiency does. 

I can't see how either of these types of anemias, while definitely problems in their own right due to low red cells, etc., could have anything thing do with low total blood volume, in response to the question asked by the Pistol. Physiologically, the mechanisms are different. Even though the cell counts are low, plasma would normally replace the decrease in total blood volume. I could be wrong, but that's the normal mechanism. In POTS, there can be low blood volume caused by a different mechanism along with the anemia though. In this case, it would be harder to determine the low red cells since the hematocrit would be pseudo normal due to decreased plasma volume.

As for the secondary erythroid hyperplasia noted in your bone marrow -- this is an increase in immature red cells being produced in the bone marrow secondary to the anemia process, an expected finding. 

What autoimmune disease do you have? Increased IgG levels indicate an over-active immune system.

On 3/14/2019 at 3:49 PM, KiminOrlando said:

One of my doctors said that the 'normal' ranges on many of these tests were established years ago when it was not common to include many women as test subjects. She also said 'normal' for men and women can be very different on some things like thyroid. What is your opinion on this?

This is where stuff gets too complex for me. 

Many if not most tests now have normal ranges established for men and women when the values are different by sex, and often even by age when that matters. In fact, many normal ranges are specific and may be slightly different to each lab depending on the type of equipment or technique used to measure the values. It's true not all tests have these updated or more specific normals, but I would think this is more rare as time goes by and the normal values are contested by other corroborating tests to show the inaccuracies of them.   

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@toomanyproblems - I think you lost me there!! I need to keep reading your info to understand it all. So - do you mean that a low RBC count but a high MCV ( and slightly high MCHC ) does not have an impact on the "viscosity" ( for lack of better words ) of the blood? 

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9 hours ago, Pistol said:

@toomanyproblems - I think you lost me there!! I need to keep reading your info to understand it all. So - do you mean that a low RBC count but a high MCV ( and slightly high MCHC ) does not have an impact on the "viscosity" ( for lack of better words ) of the blood? 

It should be the MCH that's increased along with the MCV not the MCHC. A MCHC over 36% is usually a technical error. But no, the increased red cell size by itself should not increase the viscosity of the blood in any meaningful way. I'll look into it some. But I've never seen an association with high MCV and problems like total blood volume or viscosity.

Do you have any other abnormal findings that might go with the high MCV? There may be a correlation in another associated abnormality.

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