The average 95% confidence limit of the analytical sensitivity of the test is less than 5 pg/mL (95% con- fidence interval 0.2-4.8 pg/mL). The average total imprecision is 10.1% at mean values of 28 pg/mL and 16.2% at mean levels of 1080.4 pg/mL. There is no significant cross-reactivity with endothelin-1, -atrial natriuretic peptide, or aldosterone