Bone marrow report

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isaishere

isaishere

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Hi all!
Please if you could help me....where can I find (hematopathologytextbook, surgical Pathology, articles, web sites...) the meaning of bone marrow report
especifically the

"myeloid:erythroid ratio (M:E ratio), and whether normal, increased or decreased"

I need to know what does it mean when you say M:E ratio 3:1?? 5:1?
What is the correct method to make this proportion?
If you have 10 cells, how can I get the ratio in numbers?

Thanks in advance
Ps. If you can provide me the source, more than welcome

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As you may know, in simplistic terms the bone marrow consists of myeloid cells, erythroid cells, and megakaryocytes. Since megakaryocytes rarely take up a significant volume, they are ignored in this instance.

So that leaves us with myeloids and erythroids. Normally there are about 2-3 times as many myeloids as erythroids, so M:E ratio would be 2-3:1. If you have myeloid hyperplasia and/or erythroid hypoplasia the ratio goes up. If you have myeloid hypoplasia and/or erythroid hyperplasia the ratio goes down.

There may also be relative changes, where both myeloids and erythroids are increased or decreased in the same direction, but in uneven proportion. This is probably beyond the scope of your question.

The two major ways to determine the M:E ratio are 1) by looking at the marrow and formulating a visual estimate, and 2) by doing a differential count of the cells in the bone marrow aspirate.
 
Thank you, ok lets say, when you look at the scope, you identify 10 cells,
6 are myeloid, and 3 erythroid..... Can we say M:E ratio 2:1?
How many of them (10 cells) are 5:1? 3:1?
How can I express the ratio in numbers, sorry, perhaps it is a silly Question.
 
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isaishere said:
Thank you, ok lets say, when you look at the scope, you identify 10 cells,
6 are myeloid, and 3 erythroid..... Can we say M:E ratio 2:1?
How many of them (10 cells) are 5:1? 3:1?
How can I express the ratio in numbers, sorry, perhaps it is a silly Question.
Click to expand...

Bone Marrow cell counts are done in batches of 100s of cells.. (200 cell count, 500 cell count...)
The ratio is ratio of the percentage myeloid to erythroid cells...
50% myeloid to 25% erythroid would be a M:E ratio of 2:1.

Are you asking how you can back convert a ratio to a percentage? (can't be done, without more information)
 
isaishere said:
That's the answer!!!! Many thanks

Where can I find an article that tell me this info,
I mean, the report.... I saw a sample report here:

http://www.pathologyoutlines.com/bonemarrow.html#howtoexamine
Click to expand...

Really quick...

Generally (though specifics vary from institution) bone marrow bx's include a clot section (blood clot from the marrow bx), an aspirate smear (which hopefully has spicules of marrow to assess myeloid / erythroid morphology) and (usually) a biopsy (to assess marrow cellularity, fibrosis [fibrosis = usually bad...eg: myelodysplastic process...also usually assessed with a reticulin stain or something to highlight fibrosis], etc.)

The clot section, along with aspirate smear, give you a picture of myelopoiesis, erythropoiesis and (usually) megakaryopoiesis (WBC, RBC and pletelet production). Items specifically assessed include whether or not the various cells in those lines are increased or decreased, morphology (eg. atypia present?), and particular attention to anything that could be considered a neoplastic processes (eg. if there is an increase in blasts, maturation arrest, etc).

Nowadays many / most heme cases are accompanied by flow cytometry, which gives an accurate assessment of the various myeloid populations in regards to what cell surface markers they are expressing, which are linked diagnostically & prognostically to the various hematologic malignancies. Additionally, cytogenetics may be performed (ie. a karyotype to assess for any chromosomal anomolies that are diagnostic for many of the various leukemias / lymphomas / etc.)

The WHO standard, if I recall, is the all BMs should also be signed out with a peripheral blood smear to quantitiatively & qualitatively assess the myeloid / erythroid cell lines (eg. left shift? blasts present?) outside the marrow, and to give an accurate assessment of RBC morphology that will hopefully correlate with the CBC (microcytic? nucleated RBCs? schistocytes? etc..)
 
Which books I should read in terms of how to do Differentials, examin BM bx, ect.?

schrute said:
Really quick...

Generally (though specifics vary from institution) bone marrow bx's include a clot section (blood clot from the marrow bx), an aspirate smear (which hopefully has spicules of marrow to assess myeloid / erythroid morphology) and (usually) a biopsy (to assess marrow cellularity, fibrosis [fibrosis = usually bad...eg: myelodysplastic process...also usually assessed with a reticulin stain or something to highlight fibrosis], etc.)

The clot section, along with aspirate smear, give you a picture of myelopoiesis, erythropoiesis and (usually) megakaryopoiesis (WBC, RBC and pletelet production). Items specifically assessed include whether or not the various cells in those lines are increased or decreased, morphology (eg. atypia present?), and particular attention to anything that could be considered a neoplastic processes (eg. if there is an increase in blasts, maturation arrest, etc).

Nowadays many / most heme cases are accompanied by flow cytometry, which gives an accurate assessment of the various myeloid populations in regards to what cell surface markers they are expressing, which are linked diagnostically & prognostically to the various hematologic malignancies. Additionally, cytogenetics may be performed (ie. a karyotype to assess for any chromosomal anomolies that are diagnostic for many of the various leukemias / lymphomas / etc.)

The WHO standard, if I recall, is the all BMs should also be signed out with a peripheral blood smear to quantitiatively & qualitatively assess the myeloid / erythroid cell lines (eg. left shift? blasts present?) outside the marrow, and to give an accurate assessment of RBC morphology that will hopefully correlate with the CBC (microcytic? nucleated RBCs? schistocytes? etc..)
Click to expand...
 
Parts Unknown said:
As you may know, in simplistic terms the bone marrow consists of myeloid cells, erythroid cells, and megakaryocytes. Since megakaryocytes rarely take up a significant volume, they are ignored in this instance.

So that leaves us with myeloids and erythroids. Normally there are about 2-3 times as many myeloids as erythroids, so M:E ratio would be 2-3:1. If you have myeloid hyperplasia and/or erythroid hypoplasia the ratio goes up. If you have myeloid hypoplasia and/or erythroid hyperplasia the ratio goes down.

There may also be relative changes, where both myeloids and erythroids are increased or decreased in the same direction, but in uneven proportion. This is probably beyond the scope of your question.

The two major ways to determine the M:E ratio are 1) by looking at the marrow and formulating a visual estimate, and 2) by doing a differential count of the cells in the bone marrow aspirate.
Click to expand...

I don't know if that's true. When I was on wet heme, I used to question that. Myeloid does not equal granulocytes. Erythroids and Megakaryocytes are alse myeloids and this is proven with how the disease are classified and by the very definition of myeloid. Polycythemia Vera and Essentital thrombocythemia (a proliferation of megakaryocytes) are both myeloid neoplasms. And erythroid leukemia and megakaryoblastic leukemia are myeloid leukemias. Refractory anemia with ringed sideroblasts has dysplasia in the erythroids only and it is a myelodysplastic syndrome.

So the myeloid:erythroid ratio should be equal to all the myeloid (which includes erythroids) cells counted divide by the erythroids.

Anyone who counts up granulocytes precursors and divides them by the erythroids is calculating the M:E ratio incorrectly. They are counting the G:E ratio (granulocytes to erythrocytes).
 
schrute said:
Really quick...

Generally (though specifics vary from institution) bone marrow bx's include a clot section (blood clot from the marrow bx), an aspirate smear (which hopefully has spicules of marrow to assess myeloid / erythroid morphology) and (usually) a biopsy (to assess marrow cellularity, fibrosis [fibrosis = usually bad...eg: myelodysplastic process...also usually assessed with a reticulin stain or something to highlight fibrosis], etc.)

The clot section, along with aspirate smear, give you a picture of myelopoiesis, erythropoiesis and (usually) megakaryopoiesis (WBC, RBC and pletelet production). Items specifically assessed include whether or not the various cells in those lines are increased or decreased, morphology (eg. atypia present?), and particular attention to anything that could be considered a neoplastic processes (eg. if there is an increase in blasts, maturation arrest, etc).

Nowadays many / most heme cases are accompanied by flow cytometry, which gives an accurate assessment of the various myeloid populations in regards to what cell surface markers they are expressing, which are linked diagnostically & prognostically to the various hematologic malignancies. Additionally, cytogenetics may be performed (ie. a karyotype to assess for any chromosomal anomolies that are diagnostic for many of the various leukemias / lymphomas / etc.)

The WHO standard, if I recall, is the all BMs should also be signed out with a peripheral blood smear to quantitiatively & qualitatively assess the myeloid / erythroid cell lines (eg. left shift? blasts present?) outside the marrow, and to give an accurate assessment of RBC morphology that will hopefully correlate with the CBC (microcytic? nucleated RBCs? schistocytes? etc..)
Click to expand...

It makes sense all the correlations, having all these elements to make the best Dx.. Yeah!.. I was wondering if this topic M:E ratio is as relevant as a complete integration. Many thanks
 
pathstudent said:
Anyone who counts up granulocytes precursors and divides them by the erythroids is calculating the M:E ratio incorrectly. They are counting the G:E ratio (granulocytes to erythrocytes).
Click to expand...

You are arguing from the standpoint of cellular phylogeny, but bone marrow examination was worked backwards from the standpoint of hematology. In hematologist parlance the myeloid series refers to the granulocytic and monocytic precursors (as opposed to the lymphoid series or normoblastic series). The distinction was made from peripheral blood examination, not marrow stem cells.

That said, I fully invite you to write a paper expressing your views, in the hopes that this widely accepted and clinically useful convention be overturned. After all, generating needless confusion among practicing physicians seems to be goal of a number of academic types.
 
Parts Unknown said:
You are arguing from the standpoint of cellular phylogeny, but bone marrow examination was worked backwards from the standpoint of hematology. In hematologist parlance the myeloid series refers to the granulocytic and monocytic precursors (as opposed to the lymphoid series or normoblastic series). The distinction was made from peripheral blood examination, not marrow stem cells.

That said, I fully invite you to write a paper expressing your views, in the hopes that this widely accepted and clinically useful convention be overturned. After all, generating needless confusion among practicing physicians seems to be goal of a number of academic types.
Click to expand...

The definition of myeloid is ancient and has always included megs and erythroids.

Please see page 803 of histology for pathologists. Myeloids include granulocytes (neutrophil precursors, basophil precursors, eos precursors), megakaryocytes, monocytes, and erythroids.

To say that erythroids are not part of the myeloids in the bone marrow is making up your own definition of myeloid. If you choose to do that, there is no reasoning with you.
 
pathstudent said:
The definition of myeloid is ancient and has always included megs and erythroids.
Click to expand...

In the sense that myelo- is derived from the Greek muelos, which means marrow, then yes, any cell that inhabits the marrow can be described as myeloid. But if that's what you are after then you are talking about an anatomic compartment.

In the sense used by myself and every other person who interprets bone marrow biopsies, the word carries a different connotation.

From Munker's Modern Hematology: Biology and Clinical Management (2005):

Chapter 7: Leukocytosis, Leukopenia, and Other Changes of the Myeloid Series
Click to expand...

From Glassy's Color Atlas of Hematology (1998):

...their cytoplasm contains more and more primary granules, membrane-bound packets of enxymes which are common to all members of the myeloid series (hence the name granulocytes)...
Click to expand...

Actually, one must look no further than the names of some of the cells in the myeloid series:

Myeloblast
Promyelocyte
Myelocyte
Metamyelocyte

So no, I'm not making anything up, I merely understand that the term "myeloid" carries with it a certain degree of ambiguity that is easily dispelled with some experience in the field.
 
pathstudent said:
The definition of myeloid is ancient and has always included megs and erythroids.

Please see page 803 of histology for pathologists. Myeloids include granulocytes (neutrophil precursors, basophil precursors, eos precursors), megakaryocytes, monocytes, and erythroids.

To say that erythroids are not part of the myeloids in the bone marrow is making up your own definition of myeloid. If you choose to do that, there is no reasoning with you.
Click to expand...

M:E ratio is an established concept (which is yes a little confusing because of what Myeloid could included), but in the concept of M:E ratio Myeloid is a ratio of granulocyte related cells and precursors to erthyroid cells.

Don't claim that people are "making up your own definition", and suggest that there is "no reasoning" with them... especially if it isn't true...

I see that Parts Unknown beat me to it... I spent too long looking for clear reference of M:E ratio in a book..
 
Last edited:
I was taught to divide # or percent of grans, monos, eos and basos by the # of erythroids.
 
pathologic said:
I was taught to divide # or percent of grans, monos, eos and basos by the # of erythroids.
Click to expand...


So you would exclude precursors? It wouldn't affect it much, but the link which
schrute posted states precursors are included. Which is what I was trained to do...
 
Yes include all precursors. Mono, Seg, eo and baso precursors / erythroids precursors
 
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