YAN is made up of nitrogen from primary amino nitrogen, ammonia plus urea and all of these can be measured using the Primary Amino Nitrogen Assay Kit (K-PANOPA) plus the L-Arginine/Urea/Ammonia Assay Kit (K-LARGE). L-Arginine is measured twice because it is measured by both kits however this is accounted for in the calculation of results.
Many wine producers are not interested in measuring urea since this is usually expected to be very low and therefore does not contribute to the nitrogen value.
When this is the case users find the Primary Amino Nitrogen Assay Kit (K-PANOPA) plus Ammonia Assay Kit (Rapid) (K-AMIAR) easier to use as separate tests to measure only primary amino nitrogen and ammonia rather than using the sequential assay of the L-Arginine/Urea/Ammonia Assay Kit (K-LARGE).