Figure 3.

Comparison of serum and plasma matrices and effects of freezing on ghrelin-aAb signal strength. Different matrices from human blood and effects from repeated freezing were compared with respect to ghrelin-aAb signals, taking both total signal strength and variation of the measurement into account. (A) Signals varied when ghrelin-aAb signals from serum were compared with matched plasma preparations containing EDTA, heparin or citrate as an anticoagulant. Serum and EDTA-plasma turned out to generate the most stable signals, with serum yielding higher RLU and thus qualifying as the preferential matrix for ghrelin-aAb analysis. (B) Signal strength declined upon multiple cycles of freezing and thawing, but ghrelin-aAb were still detected with more than 85% of the original signal strength after 4 freeze-thaw cycles.