Table 1.
Total storage time and storage conditions of DBS employed in this study.
| Group | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | Storage Times (yrs) | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2013 | Collection and storage at +4 °C | Transport to UMCG + storage at −20 °C | AA measurements | 4.75–5.75 | ||||||||
| 2014 | Collection and storage at +4 °C | Storage at room temperature | 3.75–4.75 | |||||||||
| 2015 | Collection and storage at +4 °C | 2.75–3.75 | ||||||||||
| 2016 | Collection and storage at +4 °C | 1.75–2.75 | ||||||||||
| 2017 | Collection and storage at +4 °C | 0.75–1.75 | ||||||||||
Residual heel prick blood was collected from the cohort years 2013–2017. All DBS cards were stored for one year at +4 °C followed by storage at RT for another four years. This is displayed in the table in relation to the year of heel prick blood collection. For example, in the cohort of 2013, some samples are taken in January 2013 and stored at +4 °C until January 2014, while others might be collected in December 2013 and stored until December of the next year. Total storage time is always one year at +4 °C and 4 years at RT. Upon arrival at the UMCG, DBS cards were stored at −20 °C until analysis.