Influence of sample matrix and storage on BNP measurement on the Bayer Advia Centaur.
The assessment and management of congestive heart failure relies increasingly on the measurement of B-type natriuretic peptide (BNP). However, the effective contribution of this biochemical test in the clinical decision making is influenced by reliability of the measure, which also depends on several preanalytical issues. Since there is controversy on the influence of the matrix and the storage conditions on BNP measurement, we compared results of BNP in serum, K2 ethylene diamine tetra-acetic acid (EDTA) plasma and lithium heparin plasma fresh samples and in matching samples stored at -20 and -80 degrees C for 1 week. BNP measured on the Bayer Advia Centaur was systematically underestimated in heparin plasma (-47%) and serum (-62%) when compared to K2 EDTA plasma. According to the established 100 ng/L cutoff value, 25% and 37% of the fresh samples collected in heparin plasma or serum were misclassified from the reference K2 EDTA fresh specimen, respectively. When compared to the fresh specimens, the mean and interindividual bias observed for samples stored at either -20 degrees C or -80 degrees C was, overall, modest for K2 EDTA plasma (-2%) and heparin plasma (+6% and -4%, respectively), though it appeared clinically meaningful in serum (+47% and +28%, respectively). Although we can not rule out that other BNP assays using different antibodies may be not affected from degradation during storage to the same extent, results of our investigation demonstrate that K2 EDTA plasma is the most suitable specimens for BNP testing on fresh and frozen samples stored at either -20 degrees C or -80 degrees C for up to 1 week.
Lippi
Giuseppe
G
Sezione di Chimica Clinica, Dipartimento di Scienze Morfologico Biomediche, Università degli Studi di Verona, Verona, Italy. ulippi@tin.it giuseppe.lippi@univr.it
Fortunato
Antonio
A
Salvagno
Gian Luca
GL
Montagnana
Martina
M
Soffiati
Giuliano
G
Guidi
Gian Cesare
GC
D001793:Blood Preservation / Q000379:methods*; D001800:Blood Specimen Collection / Q000379:methods*; D006801:Humans; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D015203:Reproducibility of Results
D020097:Natriuretic Peptide, Brain