Having trouble within routing rule with filter on discharge date

I am looking to create a routing rule that will do the following:

When transaction is not an A03, and discharge date is valued, do not transform. 

What I am having trouble with is with the conditional for the discharge date {PV1:45}.  Not sure if I can use length here or if I can use HL7.{PV1:45}>0.  I did try that, but its not working.  Not sure what I am doing wrong.

Thanks,

Nicole