The Elecsys NT‐proBNP assay is based on two polyclonal antibodies directed at residues 1–21 and 39–50 of the NT‐proBNP molecule. Analytical performance was assessed using NCCLS protocol EP‐5A using three serum pools in a preliminary study then as part of a multicentre evaluation (16 instruments in 8 hospitals). Using pools of 350 pg/l, 8700 pg/l and 13000 pg/l single site within run %CV was 0.7–1.6 (1010) and 1.2–1.5 (2010) and between run CV 5.3–6.7 (1010) and 4.4–5.0 (2010). In the multicentre evaluation within run CV was 1.0–2.5% with total imprecision 1.5–2.5% and between labs imprecision 3.8–4.0%. Functional sensitivity of <50 pg/l and measuring range to 35000 pg/l. There was excellent agreement between instrument platforms, y=0.97x+2.6; r=1.00 (n=215) for Elecsys 2010 (x) vs. Elecsys 1010 (y) and y=1.02x−0.3; r=1.00 (n=99) for Elecsys 2010 (x) vs. E 170 (y). Serum and heparin plasma samples showed good agreement but lower values were seen in EDTA plasma. Samples were stable for 7 days at room temperature; 21 days at 4 °C and for 5 freeze thaw cycles. Samples were obtained from a population of 1205 (671 male, 534 female) apparently healthy individuals screened by echocardiography and symptom questionnaire. There was poor correlation with NT‐proANP (ELISA) (rs 0.33) and modest correlation with BNP (rs 0.89) with NT‐proBNP values approximately 5 times greater than BNP (Biosite Triage). In a subset of 320 with normal ejection fraction (>50%) and no risk factors, NT‐proBNP values increased with age and were higher in women than men.