Which way is up on the Phosphate test strip?

The pad for reading the results is the one at the bottom of the channel or well. When laid on a table with the “bump” facing up, it is the pad you can see. This is going to be the darker pad.

The other pad is flush with the “back” of the strip. When constructed, the first pad (the one to read) is laid in the channel and the second pad placed on top of the first pad. The two pads are then secured in place by taping the back of the card.