Blood-collecting methods affect blood sAPP770 levels.
A, citrated plasma, heparinized plasma, and serum samples collected from healthy volunteers at 8:30–9:30 a.m. were analyzed to determine the sAPP770 levels (n = 10). Serum sAPP770 was measured at a 1:150 dilution ratio and is expressed as the mean ± S.D. **, p < 0.01; one-way ANOVA with Tukey's multiple comparison test. B, blood samples collected in citrated or heparin-containing tubes were kept at 25 °C for 0–2 h and then were centrifuged at 1,000 × g for 15 min to collect plasma and measure the sAPP770 levels (duplicate measurement). C, citrated plasma and serum samples, collected from healthy volunteers at 8:30–9:30 a.m., 12:30–1:30 p.m., and 5:00–6:00 p.m., were analyzed to determine the sAPP770 levels (n = 10). All data are expressed as means ± S.D. N.S., not significant; one-way ANOVA with Tukey's multiple comparison test.