Calculation needed for converting percent to absolute for neutrophil count

Hello blazegel,

I used to use this formula quite often when working in a heme/onc lab,
before our hematology analyzers printed out all the parameters. Today
I actually had to work it out on paper as I no longer had it down pat.

If you are calculating the absolute WBC from the automated CBC, add up
all of the differential WBC  parameters your analyzer reports, but NOT
the total WBC. (Some analyzers measure immature forms such as blasts,
myelos, metas, and  bands separately.)

Example:

Total WBC = 1500
Neutrophils = 3%
Blasts =1%
Absolute = 60 


1500 x .04 = 60 
(WBC)  x  (per cent of neutrophils and blasts)

This formula applies to manual differential counts as well as
automated differentials.

Your laboratory protocol may, however exclude immatures, or blast
forms only, from the calculation,depending on the hematological
picture of the patient.

If you go to this eMedicine site, there is an actual online calculater
for you to use!
http://www.emedicine.com/splash/etools_xml.pl?file=0absolute_neutrophil_count&prog=edcalc

 If  this is not the answer you were hoping for, please request an
answer clarification.

Regards,
~ crabcakes

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Request for Answer Clarification by blazejel-ga on 18 Sep 2002 10:41 PDT

I am looking for a conversion.  Some diffs are reported in as absolute
or percents.  I need to know how to convert from absolute to percent. 
I believe that you must divide by 1000, but just need it verified.

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Clarification of Answer by crabcakes-ga on 18 Sep 2002 10:54 PDT

I am sorry you were unhappy with the answer. Had you asked for your
clarification, and waited before you rated it, I would have gotten you
the calculation you asked for.

However, you DID ask for

percent to absolute

in your question.


In your clarification, followed immediately by a poor rating, you said
you wanted

absolute to percent

I gave you what you asked for in the question.

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Clarification of Answer by crabcakes-ga on 18 Sep 2002 18:47 PDT

blazegel/bookitty
Here is the formula you requested in the clarification:

To go from ABSOLUTE to PERCENT :

Absolute count divided by the WBC = %

Example:

Absolute = 67    WBC= 2000

Divide 67 by 2000 to get 0.0335 (then multiply by 100 to get the
percent expressed in a whole number = 3.35 % , or more commonly
rounded up to 4%

I could find no online site to back this up. I just had to work the
PERCENT to ABSOLUTE backwards.

This should do it.
~ crabcakes

PS. I tried several calculations up and down, to verify, but you may
get to a WBC count-absolute count ratio that is too low to calculate.

Good answer, wrong interpretation, not the one I was looking for.