For peace of mind, you can always test your 4.0 batch with a validity test strip to make sure that the creatinine, SG, pH, etc are all still okay.

You can find these test kits cheap by doing a Google search for drug adulteration test kits.

Keep in mind that expired/bad QF batches can be exchanged for current ones FOC at Spectrum Labs. Contact info can be found on the urineluck website.