Thursday, December 27, 2012

H/H

Is there any particular reason we always report the hemoglobin and hematocrit, consider they're almost always equivalent tests? What do we gain by listing both or calling it h/h or any of that?

14 comments:

  1. Good consider almost test very hard good

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  2. My hospital has been pushing us to pick one and order only that test.

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  3. Isn't it mostly to clarify the type of anemia? If the Hb tells you that you are anemic, doesn't the Hct tell you if it is hypochromic/normochromic, thereby supporting the information gleaned for the MCV. Granted, as a GI doc, I tend to look mostly at the MCV and RDW, but I know that a .ot of others look at both.

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  4. They are not equivalent. Hematocrit will be higher than expected for the Hb level in cases of hypochromic anemias. Its useful when MCH isnt available ie when RBC indices or a smear hasnt been done.

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    1. I understand there are theoretical reasons why one might order both, but they are generally equivalent, and I've never been involved in a real life situation where it's actually been useful because the RBC indices are always available. Have you ever been involved in a case where you were like, "Wow, good thing I had both the hgb AND the hct!" I mean, why not just order every single test there is because of some situation where it might theoretically be useful?

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    2. True.
      Yes, no point ordering both Hb and Hct when indices are available. But this question arises when they are measured manually, right? In our lab, the automated cell counter measures Hct before it does the counts and indices.

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  5. What's are hemoglobin and hematocrit?

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  6. there's a rule that says 3 times ery count = hgb * 3 = hct
    it's for plausability control... maybe it has something to do with that?

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  7. Around here we just order "CBC" so we get everything either way. I don't always pay much attention to the Hct, but it can help confirm a dilutional "anemia" in patients who have received extensive fluid resuscitation.

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  8. In my clinical experience (ICUs and ERs) at the Big Medical Center we looked only at the Hct. (I assumed that in medical outpatient departments, people studied hemoglobin and RBC indices, but we pretty much ignored them.) Imagine my shock when I went to another hospital and people were using Hgb as the baseline value. I had to learn a whole new 'language.' To this day, though, I still look to the old familiar Hct first; the Hgb is a poor step-sister. Fizzy, I think if you went to one test only, like the Hgb, you would get an argument from the Hct lovers like me. Tricia

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    1. I mostly just look at hct too.

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  9. Forgive my new found ignorance - but I just took my first semester of nursing fundamentals, and we were taught the "Rule of 3". Hgb x3= hct. Hgb x3 < hct = dehydration. Hgb x 3> hct = fluid overload.

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    1. I would mostly look at BUN/Cr as a sign of dehydration. I've never seen anyone write a note where they used that calculation to determine if a patient was fluid overloaded or dehydrated.

      And what is the margin of error there? It's unlikely that the hgb x 3 will be EXACTLY equal to the hct because the body just isn't that perfect. Does it need to be off by 0.1? 0.5? 1?

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    2. Beats the heck out of me! I am just telling you straight from my notes, the "Rule of 3" that was taught to me. I have yet to see or use it in real clinical experience.

      What I have used in my limited semester of clinical experience is using skin turgor as a sign of dehydration, and weight gain as the first sign of fluid overload.

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