May 25, 2015
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Q. In pathoma it's mentioned that-"Although Hb and Hct and RBC count are usually used as a surrogates for RBC mass, but in some circumstances they are not a good estimate of RBC mass". Can anybody cite hematological disorder with brief explanation that clarifies Hb, hct and RBC count can't always be used as a good surrogate for RBC mass.What exactly is RBC mass? Is it the total no. of RBCs in circulation? Thanks.
 
Aug 10, 2015
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RBC mass is exactly what it sounds like. More RBC = higher RBC mass (i.e polycythemia vera). More salt in a spoon is higher salt mass. Sometimes when you have a proportional loss of solvent from the blood, you can have a rise in hct. In such a case, RBC mass didn't change, but the solution it was in DID change. I believe that's what it's referring to.
 
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May 25, 2015
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Thanks silverish for such a good explanation of RBC mass. Can anybody give example of any disorder which shows Hct/Hb/RBC count doesn't always hold proportional relationship with RBC MASS?
 

Entadus

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Dehydration, pregnancy
 
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May 25, 2015
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Thanks all for the examples and explanations.
 
Jul 11, 2015
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Thanks silverish for such a good explanation of RBC mass. Can anybody give example of any disorder which shows Hct/Hb/RBC count doesn't always hold proportional relationship with RBC MASS?
Dehydration?