Table 3.
Reliability of NfL concentrations at different freezing intervals compared to immediate freezing.
| Freezing interval: 3 days RT | Freezing interval: 3 days 4–8 °C | Freezing interval: 7 days RT | |||||||
|---|---|---|---|---|---|---|---|---|---|
| iSD [x10e3pg/L] | iCOV (%) | ICC | iSD [x10e3pg/L] | iCOV (%) | ICC | iSD [x10e3pg/L] | iCOV (%) | ICC | |
| (a) sNfL | |||||||||
| Whole cohort | 1.5 | 10.2 | 0.97 | 1.7 | 9.7 | 0.98 | 1.3 | 9.0 | 0.99 |
| 0.3–2.6 | 8.2–12.2 | 0.94–0.99 | 0.9–2.6 | 6.5–12.8 | 0.96–0.99 | 0.5–2.0 | 6.5–11.5 | 0.97—0.99 | |
| Lowest quartile | 0.5 | 7.0 | 0.90 | 0.4 | 9.5 | 0.91 | 0.5 | 8.1 | 0.90 |
| 0.1–0.9 | 3.5–11.0 | 0.65–0.94 | 0.2–0.6 | 2.5–16.4 | 0.66–0.94 | 0.1–0.8 | 2.0–14.2 | 0.64–0.93 | |
| Highest quartile | 3.4 | 11.1 | 0.92 | 4.3 | 10.2 | 0.94 | 2.7 | 8.5 | 0.95 |
| 1.5–8.4 | 3.6–18.5 | 0.60–0.98 | 1.2–7.3 | 1.1–21.4 | 0.69–0.99 | 0.5–5.9 | 0.5–16.6 | 0.78–0.99 | |
| (b) pNfL | |||||||||
| Whole cohort | 1.3 | 11.6 | 0.98 | 1.7 | 8.9 | 0.96 | 0.7 | 6.5 | 0.94 |
| 0.6–2.0 | 8.1–15.1 | 0.96–0.99 | 0.6–2.7 | 6.5–11.2 | 0.92–0.98 | 0.4–1.1 | 4.8–8.2 | 0.90–0.99 | |
| Lowest quartile | 0.4 | 16.3 | 0.90 | 0.6 | 7.8 | 0.90 | 0.5 | 7.6 | 0.88 |
| 0.2–0.6 | 7.2–25.4 | 0.61–0.92 | 0.2–1.0 | 4.1–11.5 | 0.60–0.93 | 0.3–0.7 | 3.4–11.8 | 0.59–0.91 | |
| Highest quartile | 3.4 | 14.2 | 0.91 | 4.5 | 11.9 | 0.86 | 1.7 | 5.6 | 0.84 |
| 0.6–6.2 | 2.8–25.6 | 0.53–0.98 | 0.2–9.0 | 6.2–17.6 | 0.27–0.98 | 0.1–3.3 | 0.4–10.6 | 0.59–0.90 | |
Mean values and 95% confidence intervals for (a) serum neurofilament light chain (sNfL) and (b) plasma neurofilament light chain (pNfL).
ICC intraclass correlation coefficient, iCOV intraindividual coefficient of variance, iSD intraindividual standard deviation, pNfL plasma neurofilament light chain, RT room temperature, sNfL serum neurofilament light chain.