Here are the AP test kits that I've found to work in FW and SW:
Ammonia (uses 2 different color charts)
Nitrate (uses 2 different color charts)
I use Seachem brand for Phosphate and Calcium. I know the phosphate works in SW and FW. never tried the calcium kit in FW, but it should work (though testing calcium shouldn't be necessary in FW, normally).
I've heard a lot of bad comments on RedSea kits being inaccurate, and as I understand, some of their kits only tell you "low, medium, high" rather than giving numeric readings.