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Lab Differential

Discussion in 'Clinical Rotations' started by medstudam, Feb 9, 2005.

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  1. medstudam

    medstudam Junior Member 5+ Year Member

    Dec 14, 2004
    I'm a bit uncertain of what exactly the Segs. and Bands mean in a lab diff. Also, in a viral condition, is it possible for the lymphocyte count to be elevated while the WBC count remains normal?
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  3. doc05

    doc05 2K Member 10+ Year Member

    May 24, 2003
    how did you get to 3rd year without learning this stuff?

    here's a start: seg=polys/PMNs/ neutrophils. look up the rest.
  4. scootad.

    scootad. Senior Member 10+ Year Member

    Jun 1, 2001
    oh lord :laugh:
  5. medstudam

    medstudam Junior Member 5+ Year Member

    Dec 14, 2004
    Spare the criticism!
  6. Munchkin6245

    Munchkin6245 7+ Year Member

    Feb 28, 2004
    Segs and Bands are the way we differentiate neutrophils in the diff. Segs have a more segmented nucleus and a band is an unsegmented nucleus. Bands are normally reported if more than 10 are seen in a 100 cell differential.

    The WBC count can be normal if the lymphocyte count is elevated.
  7. kc361

    kc361 Member 10+ Year Member

    Dec 10, 1999
    New York, NY
    I'm guessing the OP is asking what the *significance* of these items are in the differential, not necessarily their definition.

    To the OP: Think about what a band cell is - an immature neutrophil. If the differential indicates increased WBC, with a high percentage of neutrophils (segs) and increased bands, this is referred to as a "left shift." It indicates that the bone marrow is working like the dickens to pump out new neutrophils in the setting of an acute infection. Increased bands usually carries a worse prognosis than an elevated WBC without bands.
  8. medstudam

    medstudam Junior Member 5+ Year Member

    Dec 14, 2004

    Thanks for the feedback!

    THis is how I interpret the diff.
    Increased Segs. by itself = inflammation
    Increased Segs. + Bands = infection
    Increased Bands by itself = infection (something killing off the segs.(mature) therefore only Bands left or could mean leukemia producing the band cell line.)

    I have heard several different views on this from interns and residents which is the reason for the doubt!

    Clinicals ROCK!!!!
  9. cubs3canes

    cubs3canes Senior Member 7+ Year Member

    Oct 27, 2003
    This makes me think of a funny story. During our first year we had to have small group sessions. Duirng one of the cases, there was a left shift. Some one in my group asked what a left shift was. The preceptor...she is a physician, a geriatrician responded " I think that is when all of the blood cells go to the left side of the arteries and veins."

    When we left that class, we laughed for hours. Let me just say that we did not listen to anything she said in small groups for the rest of the year.
  10. scootad.

    scootad. Senior Member 10+ Year Member

    Jun 1, 2001
    Actually, while everyone seems to think they know what a left shift is, if you ask 3 people you will get 3 different answers! Its like gaydar, people know it when they see it but cant come to a consensus about what it is. Some think that the presence of bands alone (bandemia) is equivalent to a left shift. Others will say a higher than normal PMN % is equivalent to a left shift (with or without bands, with or without higher than normal white count). Still others will say a left shift is a higher than normal PMN % in the presence of a leukocytosis and a bandemia. I cant tell you how many times I've heard people use different definitions during my rotations. :laugh:

    whatever it is, it implies acute bacterial infection.
  11. omfsres

    omfsres 5+ Year Member

    Nov 1, 2004

    What about neutrophils >80%
  12. rxfudd

    rxfudd 1K Member 10+ Year Member

    Feb 13, 2001
    Chicago suburbs
    Our immuno professor in 1st year was all too proud of the fact that he was one of the few people who actually know what the term left shift means. He says that historically, they used to use a counting device to record the differential on a CBC. The button that counted bands was the furthest button to the left, so when there was an acute infection/inflammation, you would be hitting that button much more frequently than usual because you had a bandemia (hence the term "left shift"). From that story, I would argue (and I've been told by most of my attendings) that a left shift is strictly an increase in immature cells (bands).
  13. cubs3canes

    cubs3canes Senior Member 7+ Year Member

    Oct 27, 2003

    My histo profressor taught it like this: She turned the blood cell flow chart on its side, so that the hematopoietic stem cell was on the left and the mature RBC's and WBC's were on the right. Therefore, if you have a bandemia or lots of immature cells you are on the left side of the page. If you have lots of mature cells, you are on the right side of the page and that would be a right shift.

    It would have been better if they used terms like down stream or up stream on the flow chart, but whatever. I agree it means acute bacterial infection, give antibiotics after BCx X 2 in two different places, if you suspect endocarditis, do it three times.

    I am on Medicine Wards and you can tell.
  14. ramini


    Feb 5, 2007
    I realize this may be elementary...

    How does one calculate the band cell ratio? Isnt there a formula that you can used to determine whether or not a patient is under current infection? Also is it different in peds?

  15. edmadison

    edmadison 1K Member 10+ Year Member

    Feb 27, 2001
    Lactate > 15
    Wow, I thought everyone knew that!

  16. QuinnB

    QuinnB Junior Member 10+ Year Member

    Jul 22, 2006
    it technically can include things earlier than bands, although the significance of a blastemia left shift is completely different (AML) compared to a bandemia left shift (acute bacterial infection).

    Our profs told us that they used to write cell lineage differentiation from left to write (like we read) with the hematopoeitic cells on the far left and the PMN, eos, baso, etc...on the far right. The counters were then designed with this "convention" in mind, although they only counted as far left as bands as opposed to the hematopoetic cells.
  17. DOtobe

    DOtobe 10+ Year Member

    Dec 12, 2000
    Pittsburgh, PA
    I never knew this until the attending on my last rotation (ID) told me this. I guess he's one of the few too, lol. :)
  18. Slothbear

    Slothbear 2+ Year Member

    Apr 26, 2007
    Washington DC
    yo -- don't get sucked into thinking inc bands = acute bacterial infection necessarily. It means there is acute inflammation -- one cause can be bacterial infection. You see inc bands with acute pancreatitis.
  19. lapelirroja

    lapelirroja Physician Assistant 2+ Year Member

    Jan 26, 2008
    doing a 100 cell diff (or 200) is still performed on a button counter...it's not really 'historical.' if automated methods produce strange data or if the machine is not sure what it is seeing, a manual diff is performed as a reflex test.

    --med tech

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