Effects of sample handling on serum N-terminal proB-type natriuretic peptide concentration in normal dogs and dogs with heart disease.
OBJECTIVE
To determine whether serum N-terminal B-type natriuretic peptide (NT-proBNP) concentration in normal dogs, and dogs with heart disease, is affected by freezing, or by sample ageing when stored at room temperature.


METHODS
Thirty six dogs with heart disease and ten normal dogs. Serum NT-proBNP was measured within 60 min of sample collection. Serum was also frozen at -20 degrees C and NT-proBNP measurement was repeated at 1, 24, 48, 72 and 96 h after thawing.


RESULTS
Median NT-proBNP increased significantly after freezing (p<0.005) and then progressively decreased at all time points after thawing (p<0.005).


CONCLUSIONS
Serum NT-proBNP concentration increases with freezing, and then rapidly decreases over time when stored at room temperature. Concentrations were sufficiently increased after freezing and decreased after 24h at room temperature to affect interpretation. The authors recommend that serum for NT-proBNP assay should be frozen within 1h of sampling and submitted frozen in cold packs.
Southern Counties Veterinary Specialists, 6 Forest Corner Farm, Hangersley, Ringwood, Hampshire, BH24 3JW, United Kingdom. stephen.collins@scvetspecialists.co.uk
Stephen A
SA
Collins
Mark W
MW
Patteson
David J
DJ
Connolly
Dave C
DC
Brodbelt
Andrew G
AG
Torrance
Joanne D
JD
Harris
D000818:Animals; D001800:Blood Specimen Collection / Q000662:veterinary; D015925:Cryopreservation / Q000662:veterinary; D004283:Dog Diseases / Q000097:blood* / Q000503:physiopathology; D004285:Dogs; D006331:Heart Diseases / Q000097:blood / Q000662:veterinary*; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D013048:Specimen Handling / Q000662:veterinary*; D013997:Time Factors
D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain