Anisidine value (AV) is a measurement of past oxidation. Precisely, it is the measure of aldehyde production during oxidation of fats. AV essentially reflects how an oil has been handled and stored versus peroxide value (PV), which measures current oxidation. For both AV and PV, a lower number is better. TOTOX (total oxidation value) is used to describe total oxidation to which an oil has been exposed. PV x 2 + AV = TOTOX Recent tests of Nordic Naturals fish oils report TOTOX values of 7.0. Our oils typically range between 5 and 14.