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Old 05-05-2014
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Default Concomitant Deficiencies & Blood Results

I'm trying to establish how, in hematological terms, an iron deficiency can mask a b12 deficiency. The question is in respect of the paragraph below - ie, I know it can do it, but I don't know how?

Many thanks.

"Vitamin deficiency (b12) may be present without macrocytosis particularly when there is a concomitant iron deficiency or thalassaemia trait. There may be a dimorphic red cell population and macrocytosis may only become manifest when iron deficiency has been corrected. Neutrophil hypersegmentation is not specific...In addition it is not present in every patient with vitamin deficiency (which we've covered), its absence is especially to be noted in patients who are seriously ill and neutropenic."
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Old 05-05-2014
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I think it can mask it in terms of the red blood cell size.
The way I think of it:
Iron deficiency anemia --> Microcytic anemia
B12 deficiency anemia --> Megaloblastic MACROCYTIC anemia
These things cancel out and patients end up with a seemingly normal or slightly low MCV, steering us away from the diagnosis of a macrocytic anemia. Once you correct their iron deficiency their MCV should increase "uncovering" their B12 deficiency.

Dr. Goljan mentioned this in one of his Heme lectures. I highly recommend listening to them if you have the time
"There's always a siren singing you to shipwreck."
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Old 05-05-2014
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Originally, Noa, that's what I thought - a microcytic cancelled out a macrocytic - but then I thought I was being too simplistic because a macrocytic is based on the size of the cells and a microcytic based on the hemaglobin, so it's not a large cell v small cell situation.
It's essentially why I was asking.

Of course we then have the situation that if you have the 2 deficiencies and no sign of either macro or micro, then usually a deficiency is not looked for because there is no original indication of a need for it. So the iron deficiency doesn't get picked up and the b12 deficiency is not revealed.

Thanks for the Dr Goljan tip!
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