title: Analytical performance and clinical results of a fully automated MEIA system for brain natriuretic peptide assay: comparison with a point of care testing method.
abstract: The aim of this study was to evaluate the analytical performance of a recently available immunoassay for brain natriuretic peptide (BNP), based on microparticle enzyme immunoassay (MEIA, AxSYM System, Abbott Laboratories), whose analytical characteristics and clinical results were compared with those of a point of care testing (POCT) method (TRIAGE system, Biosite Diagnostics). The within-run and total imprecision of the MEIA system were 18.4% and 19.8% at 21 ng/l, 8.0% and 14.8% at 183 ng/l, and 5.7% and 14.0% at 319 ng/l, respectively. The detection limit of the MEIA system was tested by repeatedly measuring (n=20) the 0 calibrator in four different runs; a mean +3 SD value of 5.6+/-4.8 ng/l (range 1.8-12.6 ng/l) was obtained. A close linear relationship (MEIA= -22.5+/-1.71 POCT method, R=0.950, n=296) was found (BNP concentration: 5-5500 ng/l), with a significant bias (mean difference: 164.8 ng/l, p<0.0001). Mean BNP concentration measured in 94 reference subjects (57 women and 37 men; mean age 43.5+/-14.0 years) was higher with MEIA than POCT, (25.9+/-32.7 ng/l vs. 11.7+/-8.9 ng/l, p<0.0001). The same trend was observed also in 202 cardiac patients (620.6+/-1082.2 ng/l vs. 386.1+/-594.5 ng/l, p<0.0001). Our data suggest that MEIA and POCT have quite similar analytical performance but different clinical results. Then, different reference values, as well as cut-off values, should be taken into account for the clinical use of these two immunoassays.
authors.affiliation: Laboratory of Cardiovascular Endocrinology, CNR Institute of Clinical Physiology, Pisa, Italy. storti@ifc.cnr.it
authors.forename: Simona
authors.initials: S
authors.lastname: Storti
authors.forename: Concetta
authors.initials: C
authors.lastname: Prontera
authors.forename: Michele
authors.initials: M
authors.lastname: Emdin
authors.forename: Claudio
authors.initials: C
authors.lastname: Passino
authors.forename: Paola
authors.initials: P
authors.lastname: Prati
authors.forename: Giuliana
authors.initials: G
authors.lastname: Fontani
authors.forename: Isabella
authors.initials: I
authors.lastname: Giannelli
authors.forename: Luc
authors.initials: L
authors.lastname: Zyw
authors.forename: Simona
authors.initials: S
authors.lastname: Vittorini
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Zucchelli
authors.forename: Aldo
authors.initials: A
authors.lastname: Clerico
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001331:Automation; D002624:Chemistry, Clinical; D002648:Child; D002675:Child, Preschool; D005260:Female; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000145:classification / Q000379:methods*; D007223:Infant; D008297:Male; D008875:Middle Aged; D036103:Nanotechnology; D020097:Natriuretic Peptide, Brain / Q000097:blood* / Q000737:chemistry; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D006454:Hemoglobins; D020097:Natriuretic Peptide, Brain