A summary of previous studies on the stability of metanephrine and normetanephrine in plasma or urine
| Reference | Specimen | Levels | Method | Conditions | Results | |
|---|---|---|---|---|---|---|
| Temperature (℃) | Duration | |||||
| Willemsen et al. [11] (2003) | Whole blood plasma | 1 | HPLC | RT (for whole blood) | 6 hours | In whole blood, unstable at RT; in whole blood, stable within 6 hours at 4℃ |
| RT (for plasma) | 3 days | In plasma, unstable at RT | ||||
| 4, –20 (for plasma) | 1 month | In plasma, stable within 3 days at 4℃; in plasma, stable within 1 month at –20℃ | ||||
| de Jong et al. [12] (2007) | Plasma | 3 | LC-MS/MS | RT | 24 hours | In plasma, stable within 24 hours at RT |
| 10, 4 | 7 days | In plasma, stable within 7 days at 10℃ and 4℃ | ||||
| Freeze (–20)/thaw (RT) | 3 cycles | In plasma, stable in 3 freeze-thaw cycles | ||||
| Ross et al. [13] (2011) | Plasma | 1 | HPLC | –20, –80 | 60 months | In plasma, stable within 12 months at –20℃ and –80℃ |
| Danese et al. [4] (2020) | Whole blood plasma | 1 | LC-MS/MS | RT, 4 (for whole blood) | 3 hours | In whole blood, unstable at RT; in whole blood, stable within 3 hours at 4℃ |
| RT, 4 (for plasma) | 6 hours | In plasma, stable within 6 hours at RT and 4℃ | ||||
| Wang et al. [3] (2021) | Whole blood plasma | 2 | LC-MS/MS | RT, 4 (for whole blood) | 4 hours | In whole blood, unstable at RT; in whole blood, stable within 4 hours at 4℃ |
| RT, 4 (for plasma) | 6 hours | In plasma, stable within 6 hours at RT and 4℃ | ||||
| –20, –80 | 7 days | In whole blood & plasma, stable within 7 days at –20℃ and –80℃ | ||||
| Chan et al. [14] (2000) | Urine with/without preservatives | 1 | HPLC | 10, 30 | 8 days | In urine without/with preservatives, unstable at 10℃ and 30℃ |
| –80 | 1 month | In urine without/with preservatives, stable within 22 days at –80℃ | ||||
| Willemsen et al. [15] (2007) | Urine with/without preservatives | 1 | HPLC | RT | 7 days | In urine without/with preservatives, stable within 7 days at RT |
| Peitzsch et al. [16] (2013) | Urine with/without preservatives | 1 | LC-MS/MS | RT | 3 days | In urine without/with acidification, stable within 3 days at RT |
| Urine with strong acidification | RT | 3 days | In urine with strong acidification, unstable (especially, normetanephrine) | |||
| Wang et al. [17] (2020) | Urine without preservatives | 1 | LC-MS/MS | RT, 4 | 4 days | In urine without preservatives, stable within 4 days at RT and 4℃ |
| –20 | 7 months | In urine without preservatives, stable within 7 months at –20℃ | ||||
| This study (2022) | Plasma urine without preservatives | 2 | LC-MS/MS | RT | 24 hours | In plasma/urine, stable within 24 hours at RT |
| 4, –20 | 8 days | In plasma/urine, stable within 8 days at 4℃ and –20℃ | ||||
| –80 | 7 months | In plasma/urine, stable within 7 months at –80℃ | ||||
| Freeze (–20)/thaw (RT) | 3 cycles | In plasma/urine, stable in 3 freeze-thaw cycles | ||||
| With dry-ice | 7 days | In plasma/urine, stable within 7 days with dry-ice | ||||
Abbreviations: HPLC, high performance liquid chromatography; RT, room temperature; LC-MS/MS, liquid chromatography-tandem mass spectrometry.