Is this the first test you've done? How long has the tank been cycling for?
Typically during the cycle process you will see fluctuations of ammonia, trites and trates. Waiting to see these levels disappear is part of the patients game, but waiting for a while after everything has zero'd out is also part of the waiting game. After a few days if there is still no readable traces or just some nitrates then I would say your tank is cycled. HTH.