Analytical performance of the N terminal pro B type natriuretic peptide (NT-proBNP) assay on the Elecsys 1010 and 2010 analysers.
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 degrees 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.
Department of Chemical Pathology, St. George's Hospital, Blackshaw Road, London, SW17 0QT, UK. paul.collinson@stgeorges.nhs.uk
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Collinson
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Barnes
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Gaze
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Galasko
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Lahiri
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Senior
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*
D015415:Biomarkers; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain