Re: Reply to T.Vincent Shankey

Walter Sharp (102675.320@compuserve.com)
01 Mar 96 02:05:59 EST

Vince,
There are several reasons why I had to find a way to lyse the preps
rather than rely on more conventional gating strategies which were giving us
problems.
1) 60% of the population of Oman has alpha Thal. trait, with MCV's in the 60-65
region very common.
Add this to a developing country's high incidence of Fe deficiency and you have
a much greater degree of RBC/PLT overlap.
Further adding to this is a wider MPV range of 6.0 to 12.0 (Coulter)
2) It cuts down on the size of listmode files if all we are storing is PLT data.
3) Why not ? -it looks prettier !

Admittedly if all one is wanting is is a yea or nay result, as in diagnosing a
Glanzmann's disease or assaying activation, then a proportion of negative RBC's
won't make much of a difference to the final answer.
Consanguinous marriages are the norm here, as is evident from the Thal traits,
so our project will include a large scale assaying of the population for
heterozygous Glanzmann's (we know there are a lot !) where the Fluorescence
means are of prime importance and which ideally should not include any false
negative data.
Also, getting rid of the RBC overlap will allow us to put large numbers of
assays on the XL's carousel and allow the instrument to "autogate" on the pure
PLT populations.
With the conventional non-lysed technique we had to manually gate on the
platelets for each patient.
I shall post this reply to the list, since I am sure that others may have the
same legitimate query as you.

Wal Sharp
SQU
Oman