Hematocrit & Hemoglobin differences in dehydration vs blood loss

[mreicher]

I'm wondering what the difference would be on the CBC for hemoglobin & hematocrit for someone with a fluid volume deficit depending on whether they were dehydrated or had blood loss.

[Neuro Guy NP, DNP, PhD, APRN]

But if you're losing blood, the percentage of H & H in the remaining blood is the same, no? Let's say you have a liter of blood(making up easy numbers), 20% of which makes up your H&H. You lose 1/4 of that blood. The remaining 3/4 of the blood is still comprised of 20% H&H, no?

I get the dehydration example, but our texts lists dehydration & blood loss under fluid volume deficit & indicates that in both instances the H&H would be increased......

Actually, it depends on whether or not the H&H will remain the same. It would remain the same if and only if the loss is an isotonic loss, RBCs, and serum components are lost in equal proportions. It is possible, and quite a risk factor for there to be alterations in H&H as I mentioned in my original answer. I verified this in Joyce Lefever Kee's "Laboratory and Diagnostic Tests". You raise a good point, though.

[Neuro Guy NP, DNP, PhD, APRN]

Here someone is trying to help the OP think a problem out and someone always comes along and just does the work for them. Always.

Sigh...

It's not a matter of doing the work for them. Most likely the individual had thought about it beforehand. Besides, why do we need to be so stingy with information? I am personally glad to help other people advance their knowledge base in any way we can. Think of when you were in nursing school. Sure you wouldn't want you professor to brush you off when you asked a question, even if the professor thought you hadn't thought it out that well.

Let's just try to help each other here. It will help us provide better care by sharing knowledge.

[P_RN, ADN, RN]

heaviest cells white=lighter plasma=even lighter

[00000000000000000000000|0000|[color=sandybrown]0000000000000000]

rbc wbc serum/plasma

ok that's a tube of normal blood.hold i t down the red cells are at the bottom, the white cells are in the middle and the liquid part is at the top.

in dehydration you lose fluid., you have the same amount of rbc as you weren't losing them or the white but the liquid part went to try to build up what dehydration cost.

so in this tube let's say the normal rbc is 16 (hgb). the hct would run about 48.

so the hct is normally near 3x the hgb.

heaviest cells white=lighter plasma=even lighter

[000000000000000000000000000[color=sandybrown]0000- [lost]

[color=sandybrown]

if you lost most of your liquid/plasma in dehydration the percentage of red cells in this tube would be higher and the hct would be higher. you replace body fluid, it gets transported in the blood, and the hgb goes back to normal.