AGTR1 and Hypertension: Measurement of AT1-AA varied by study: 7 studies used enzyme-linked immunosorbent assay (ELISA),9,16–21 2 used a neonatal cardiomyocyte contraction assay,13,15 and only 1 used a 4 × Nuclear factor of activated T-cells (NFAT)-driven Luciferase reporter assay.14 As shown in Table 3, the association of AT1-AA with hypertension is independent of AT1-AA measurement.