Analytical performance and clinical results of a fully automated MEIA system for brain natriuretic peptide assay: comparison with a point of care testing method.
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.
Storti
Simona
S
Laboratory of Cardiovascular Endocrinology, CNR Institute of Clinical Physiology, Pisa, Italy. storti@ifc.cnr.it
Prontera
Concetta
C
Emdin
Michele
M
Passino
Claudio
C
Prati
Paola
P
Fontani
Giuliana
G
Giannelli
Isabella
I
Zyw
Luc
L
Vittorini
Simona
S
Zucchelli
Giancarlo
G
Clerico
Aldo
A
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
D006454:Hemoglobins; D020097:Natriuretic Peptide, Brain