Precision Labs Nitrate and Nitrite test strips measure results as nitrite and nitrate ions, not as nitrogen content (commonly referred to as nitrite-nitrogen and nitrate-nitrogen).
It is important to know which result to report. Agricultural applications typically report results as nitrate while drinking water limits for nitrite and nitrate are expressed as nitrogen.
To convert from nitrite to nitrogen content (nitrite-nitrogen) divide the nitrite result by 3.3.
To convert from nitrate to nitrogen content (nitrate-nitrogen) divide the nitrate result by 4.4.
For example, a drinking water limit of 1 ppm nitrite (as nitrogen) is the same as a result of 3.3 ppm nitrite. Likewise, a 10 ppm nitrate limit (as nitrogen) is the same as a result of 44 ppm nitrate.