Assign if-test result value to a variable

Newbe question..

I need to assign the result of the following "if-test" statement to a
variable (result is a letter a,b,c, etc). I also need to make the
variable available to the template that I am calling in
(RevisionRecord).  I have tried numerous approaches for this but cannot
make it work.  Suggestions appreciated.

<xsl:for-each
select="//ApplicationData/Revision_Record[./RevisionLetter!='NEW']">
	<xsl:sort select="./RevisionLetter" order="ascending"/>
		<xsl:if test="position()=last()">

			<xsl:call-template name="RevisionRecord"/>

		</xsl:if>
</xsl:for-each>


Thanks in advance.
Gary