Table 2. Melatonin measurement protocols among included studies.
| Study | Sample Medium |
Assay Type |
Assay Limit | Assay CV | Melatonin sampling protocol |
|---|---|---|---|---|---|
| Kneisley et al.39 | Urine | RIA | NR | NR | 08:00–12:00, 12:00–20:00, 20:00–24:00, 24:00–04:00, 04:00–08:00 |
| Li et al.38 | Blood | RIA | NR | 6.2/16.5 | 02:00, 04:00, 10:00 and 14:00 |
| Papendorp et al.40 | Blood | RIA | NR | NR | 07:00, 14:00, 01:00 and 7:00 |
| Zeitzer et al.41 | Blood | RIA | 5 pg/ml | 8/13 | 1–3 samples/h, over 44-h total |
| Verheggen et al.49 | Saliva | ELISA | NR | NR | 19:00, 20:00, 20:30, 21:00, 21:30, 22:00, 22:30, 23:00 |
| Spong et al.50 | Saliva | NR | NR | NR | BT and UA |
| Spong et al.47 | Urine Blood |
RIA RIA |
2 ng/ml 2 pg/ml |
<15/<15 <15/<15 |
2-h BBT and UA OR urine hourly between 18:00 to 07:00 1-h BBT |
| Zeitzer et al.48 | Urine | NR | NR | NR | Overnight urine collection, times NR |
| Kostovski et al.51 | Blood | ELISA | 1 pg/ml | NR | 07:00, 12:00, 16:00, 18:00, 20:00, 22:00, 24:00, 02:00, 04:00, 07:00 |
| Fatima et al.52 | Blood | ELISA | NR | NR | 06:00, 12:00, 18:00 and 00:00 |
| Kostovski et al.53 | Blood | NR | NR | NR | Plasma samples collected 4 to 10 times during 24-h period, times NR |
| Vaughan et al.54 | Saliva | NR | NR | NR | 2-h BBT, 1-h BBT, BT, 1-h ABT |
Studies are reported with the first name of the primary author. Melatonin was assayed using either radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA). The assay coefficient of variation (CV) is reported as the intra-assay reliability (%) / inter-assay reliability (%). NR, not reported; BT, bed-time; ABT, after bed-time; BBT, before bed-time; UA, upon awakening.