Hello All,
Although the sample was indeed small in my opinion if a serious nosema, varroa or tracheal mite problem had been going on it would have turned up.

I know  Allen treats for varroa  and tracheal mites so would not expect those to turn up in such a low sample .but surprised not one varroa turned up. 

If treatment  for nosema had not been done in several years I would expect some nosema to be found even in such a low sample.
I once found nosema in 200 of 200 bees sampled in spring in a beekeepers bees.

Choose a hive at random Allen and take 100 bees and have tested as you did the 5 bees . Maybe even 200 from a random hive. 

You will then  be better able to evaluate your  5 bees per hive testing by figuring a percentage of accuracy of  5 bees to 100. 5 bees to 200.

Pick a few random hives  and  roll and sticky board to help evaluate  your testing.
. 
Sincerely,
Bob Harrison

Ps. Florida bee inspectors reported counting around  8,000 small hive beetles in one hive with heavy infestation at the meeting in Savannah.  Reports of as many as 200 tracheal mites in one bee  trachea have been reported. I have personally seen several   varroa on one bee with a heavy infestation. in spring..
In my opinion all bees in hives in Canada this time of year would give a  fairly accurate sample as all are  in cluster for most of the  time except for  possibly a few hours .