Hematocrit & Hemoglobin differences in dehydration vs blood loss

  1. 0
    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.
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  3. 14 Comments so far...

  4. 0
    OK, now think of what you just wrote... take it apart, don't overthink it.
  5. 0
    I've been thinking about it.....can't come up with a difference, which is why I asked.
  6. 5
    Define Hematocrit
    Define Hemoglobin


    Define blood loss (hint: some blood is gone...)
    Define dehydration (hint: blood is not leaving... but there is a change... )
    wooh, LPNnowRN, Chin up, and 2 others like this.
  7. 4
    Hematocrit:

    With blood loss, the hematocrit will be diminished due to blood loss which certain will include loss of RBCs (severity of decreased hematocrit dependent on severity of blood loss.

    Dehydration is loss of body water but RBC concentration as is, so the hematocrit will be increased as compared to everything else.

    So, in review, hematocrit increased w/ dehydration, decreased with blood loss.

    Hemoglobin:

    Decreased in blood loss due to RBC loss, which is where hemoglobin is bound.
    It will be increased with dehydration because there is a loss of body water. Remember that since hemoglobin is bound to the RBCs, if the RBCs are increased, then so will the hemoglobin, and vice versa. Can't think of an exception, but someone will correct me if so.

    Let me know if you have further questions.
  8. 7
    Quote from Future NP-BC
    Hematocrit:

    With blood loss, the hematocrit will be diminished due to blood loss which certain will include loss of RBCs (severity of decreased hematocrit dependent on severity of blood loss.

    Dehydration is loss of body water but RBC concentration as is, so the hematocrit will be increased as compared to everything else.

    So, in review, hematocrit increased w/ dehydration, decreased with blood loss.

    Hemoglobin:

    Decreased in blood loss due to RBC loss, which is where hemoglobin is bound.
    It will be increased with dehydration because there is a loss of body water. Remember that since hemoglobin is bound to the RBCs, if the RBCs are increased, then so will the hemoglobin, and vice versa. Can't think of an exception, but someone will correct me if so.

    Let me know if you have further questions.
    Where where you when I needed someone to do *my* homework?
    RNTOBE_1970, GHGoonette, tablefor9, and 4 others like this.
  9. 0
    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......
  10. 3
    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...
    SilentfadesRPA, wooh, and netglow like this.
  11. 0
    @CCL RN-what's an OP? I don't mind the help Future NP BC was giving. I've been trying to work it out for hours, and the way onaclearday was trying to 'help me think it out' wasn't working at all. Either way, I'm still confused.
  12. 2
    Quote from Future NP-BC
    Hematocrit:

    With blood loss, the hematocrit will be diminished due to blood loss which certain will include loss of RBCs (severity of decreased hematocrit dependent on severity of blood loss.

    Dehydration is loss of body water but RBC concentration as is, so the hematocrit will be increased as compared to everything else.

    So, in review, hematocrit increased w/ dehydration, decreased with blood loss.

    Hemoglobin:

    Decreased in blood loss due to RBC loss, which is where hemoglobin is bound.
    It will be increased with dehydration because there is a loss of body water. Remember that since hemoglobin is bound to the RBCs, if the RBCs are increased, then so will the hemoglobin, and vice versa. Can't think of an exception, but someone will correct me if so.

    Let me know if you have further questions.
    That is not exactly the best way to answer that question. Mreicher pretty much was correct in regards to blood loss. Think of a bag of packed red cells. The hematocrit averages 70%. Pour out half of the blood and while the volume has decreased the remaining blood will still have a hematocrit of 70%.

    In acute blood loss doing a CBC will not help. There would be no difference between hemoglobin and hematocrit from what it was before the bleeding occurred. After a few hours plasma volume will be replaced by fluid from the interstitial space and you will then see a decrease in H&H. Also, there are many other methods that aid in assessing blood loss and volume deficit. Lactic acid and base excess are a good place to start looking if you want to read into this topic further.
    CCL RN and mreicher like this.


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