Table 2.
The summary of laboratory methods used to measure ghrelin levels in studies on unmedicated humans with healthy control group.
| Reference | Biological material | Method | Temperature of storage (°C) | Ghrelin concentration in patients with MDD compared to controls |
|---|---|---|---|---|
| Ozsoy 2014 (15) | Serum | RAI | −70 | ↑ |
| Algul 2018 (40) | Plasma | ELISA | −80 | ↑ |
| Okasha 2022 (41) | Serum | ELISA | −20 | ↑ |
| Chen 2021 (43) | Serum | RAI | −80 | ~ |
| Giménez-Palop 2012 (44) | Plasma | ELISA (for acylated ghrelin), RAI (for total ghrelin) | −80 | ~ |
| Huang 2021 (45) | Serum | RAI | −80 | ~ |
| Barim 2009 (42) | Plasma + HCl | RAI | −20 | ↓ |
HCl, hydrochloric acid; ELISA, enzyme-linked immunosorbent assay; RAI, radioimmunoassay; MDD, major depressive disorder.
↑, higher when compered to controls; ↓, lower when compered to controls; ~, no difference between subjects and controls.