Should one expect increased reticking in Iron def anemia?

[FadingPromise]

So, with obvious classic ones like sickle cell crisis, MAHA or AIHA, of course we know that retic would be significantly elevated.

Question is whether retic is expected to be elevated with severe iron def anemia.

Case in point: A 60 yr elderly presenting with fatigue. CBC demonstrating Hg of 8.0 and MCV of 70. But retic count is 0.5%. I guess my question is whether the next test to order (in test question scenerio) is iron profile (Ferritin, TIBC, etc) or suspect renal problems (due to erythropoetin def or marrow hypocellularity). My assumption was that "normal" retic count of 0.5% in someone with Hg of 8 is not normal and ordered BMP to check renal function.

Wondering what others think about this.

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[turkeyjerky]

So, with obvious classic ones like sickle cell crisis, MAHA or AIHA, of course we know that retic would be significantly elevated.

Question is whether retic is expected to be elevated with severe iron def anemia.

Case in point: A 60 yr elderly presenting with fatigue. CBC demonstrating Hg of 8.0 and MCV of 70. But retic count is 0.5%. I guess my question is whether the next test to order (in test question scenerio) is iron profile (Ferritin, TIBC, etc) or suspect renal problems (due to erythropoetin def or marrow hypocellularity). My assumption was that "normal" retic count of 0.5% in someone with Hg of 8 is not normal and ordered BMP to check renal function.

Wondering what others think about this.

Pretty sure that a retic count is gonna be low in iron deficiency. Also wouldn't expect microcytosis in renal dz. Even ACD is usually normocytic and should not have an mcv under 75. I'd definitely say the first step is an iron panel.

 

[lisichka]

I am not sure about the pathogenesis of low retic count in iron def. anemia, but i am guessing that body likes to pop out new baby retics only when it senses that mature rbcs are lost. But in Fe def. only iron is lost, the cell itself is alive, maybe it;s not doing so well (hypochromia), but it is alive nevertheless.
I would be curious to know the real reason though

 

[umean2tellme]

How are the other cells (WBC, platelets)? She could have iron def and be bleeding somewhere, have you checked stool for blood?

 

[curley hair]

Order iron studies.If the pt has iron defiency, he needs to see a GI for a
colonoscopy.GI blood loss is the most likely cause for the microcytic anemia in this pt.
Retic count will go up iron replacement

 

[Rendar5]

Retic count is not responding appropriately by any means. A normal baseline retic at 15hgb is 1% and doubles (well a bit less) when you drop to 8hgb out of simple mathematical concerns. If the pt was responding to her anemia by increasing her reticulocyte production, you'd see it actually rise to 3-4% at least. She's simply not producing red cells

There's a lot of stuff that could be causing this, iron deficiency being the least of them. But at least you're not looking at hemolysis which narrows the differential a bit.

 

[werd]

in iron deficiency, retics are low because the body doesn't have the iron to make hemoglobin to make RBC's. retics are the body's attempt to compensate for low blood counts by throwing out immature RBC's. iron deficiency is a problem of making RBC's and so retics should also be low. i'd continue with your microcytic workup including iron panel.

 

[cpants]

Retic count is not responding appropriately by any means. A normal baseline retic at 15hgb is 1% and doubles (well a bit less) when you drop to 8hgb out of simple mathematical concerns. If the pt was responding to her anemia by increasing her reticulocyte production, you'd see it actually rise to 3-4% at least. She's simply not producing red cells

There's a lot of stuff that could be causing this, iron deficiency being the least of them. But at least you're not looking at hemolysis which narrows the differential a bit.

No.

In Fe deficiency anemia, which is the MOST LIKELY diagnosis in this patient, you don't get an elevated retic. Of the choices the OP listed, the most appropriate next step is iron studies. If they give you anything to do with checking for bleeding, that would be the right answer (vital signs, colonoscopy, fecal occult blood). In a 60 year old GI bleed and dietary deficiency are the most common causes of iron deficiency anemia.

 

[Rendar5]

No.

In Fe deficiency anemia, which is the MOST LIKELY diagnosis in this patient, you don't get an elevated retic. Of the choices the OP listed, the most appropriate next step is iron studies. If they give you anything to do with checking for bleeding, that would be the right answer (vital signs, colonoscopy, fecal occult blood). In a 60 year old GI bleed and dietary deficiency are the most common causes of iron deficiency anemia.

I realize you don't get an elevated retic in Fe Deficiency. But with a retic that low I'm more concerned with diagnosing stuff that leads to iron deficiency or, more broadly, leads to failed red cell production, than I am with establishing a dx of primary iron deficiency because that's relatively severe numbers from what I'm used to seeing in my pt population. Iron you can just replace. Pt needs a fuller workup than an iron panel unless they're guiac + (that's the first test you do in this pt). I don't think we disagree on what's on the differential, I just think we're thinking about it slightly differently.

 

[FadingPromise]

I realize you don't get an elevated retic in Fe Deficiency. But with a retic that low I'm more concerned with diagnosing stuff that leads to iron deficiency or, more broadly, leads to failed red cell production, than I am with establishing a dx of primary iron deficiency because that's relatively severe numbers from what I'm used to seeing in my pt population. Iron you can just replace. Pt needs a fuller workup than an iron panel unless they're guiac + (that's the first test you do in this pt). I don't think we disagree on what's on the differential, I just think we're thinking about it slightly differently.

Sorry about the late response.
After flipping through the book that came with this question, this basically is the official reasoning, which leads to iron study as the most important next test to order, followed by colonoscopy and etc to work it up further. But yes, as many said above, retic should go up in iron def anemia but it simply can't because there isnt enough iron in the system.

 

[lisichka]

.

 

[lisichka]

Sorry about the late response.
After flipping through the book that came with this question, this basically is the official reasoning, which leads to iron study as the most important next test to order, followed by colonoscopy and etc to work it up further. But yes, as many said above, retic should go up in iron def anemia but it simply can't because there isnt enough iron in the system.

i am prob. missing a very important and SIMPLE concept here, why do retics need normal iron amounts to grow? Can't they grow if iron stores are low? what about
folate and b12 then? i am confused🙁

 

[cpants]

i am prob. missing a very important and SIMPLE concept here, why do retics need normal iron amounts to grow? Can't they grow if iron stores are low? what about
folate and b12 then? i am confused🙁

Reticulocytes and later red blood cells are basically just bags full of hemoglobin. Each hemoglobin contains four Fe atoms. When you are short on Fe, you can't make hemoglobin, and the result is smaller RBC's (microcytic anemia). There just isn't enough hemoglobin to fill them up with. Your reticulocyte count remains normal, because the problem isn't a deficit of RBC's it is a deficit of hemoglobin. The body continues to replace RBC's as needed by making reticulocytes. Folate and B12 are a separate issue.