EFFECT OF SAMPLE STORAGE ON QUANTITATION OF LIPOPROTEIN(A) BY AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY

Citation
Rw. Evans et al., EFFECT OF SAMPLE STORAGE ON QUANTITATION OF LIPOPROTEIN(A) BY AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY, Lipids, 31(11), 1996, pp. 1197-1203
Citations number
44
Categorie Soggetti
Biology
Journal title
LipidsACNP
ISSN journal
00244201
Volume
31
Issue
11
Year of publication
1996
Pages
1197 - 1203
Database
ISI
SICI code
0024-4201(1996)31:11<1197:EOSSOQ>2.0.ZU;2-Y
Abstract
This study evaluated the effect of storage on the quantitation of lipo protein (Lp)(a) in 25 serum samples. Aliquots of serum were stored for up to three years at either -20 degrees C or -70 degrees C and Lp(a) subsequently analysed using an enzyme-linked immunosorbent assay kit. Concentrations of Lp(a) declined during storage, and the temperatures employed elicited significantly different (P < 0.05) values within 12 mon which further diverged during three years of storage. Compared to baseline values, significant decreases (P < 0.05) in Lp(a) levels were evident after six months of storage at -20 degrees C with apparent lo sses (geometric mean) reaching 36.9% (95% confidence interval: 30.9%, 42.9%) after three years. Similarly, significantly lower (P < 0.05) Lp (a) values were recorded after six months of storage at -70 degrees C and at three years the decrease (geo-metric mean) was 19.1% (95% confi dence interval: 14.3%, 24.0%). The losses, after three years, in terms of the arithmetic mean were 53.5 and 26.2% at -20 and -70 degrees C, respectively. Phenotype analysis suggested that large isoforms are mor e susceptible to degradation than smaller moieties. This may be relate d to the observation that apparent losses are reduced in samples conta ining over 8 mg/dL Lp(a). Nevertheless, Lp(ai levels in stored samples retained a strong correlation with the baseline values. These results must be considered specific for the storage conditions and analytical procedures employed.