Just if anyone's wondering ... the UNION SQL keyword does it - I wrote a new query in the Access db, thus:

SELECT * FROM Test1Yr UNION SELECT * FROM Test2Yr UNION SELECT * FROM Test5Yr;

That shows all the patients that need tests, regardless of the other criteria. Yippee!

I'm not sure this would work if the queries weren't mutually exclusive (i.e. each patient only shows up in one query.

Cheers, Peter