Correction to: Scientific Reports 10.1038/s41598-021-90639-z, published online 26 May 2021
The original version of this Article contained errors, where the intraindividual coefficient of variation (iCOV) was calculated incorrectly.
As a result, in the Results section under the subheading ‘NfL concentrations in serum and plasma withstand delayed processing up to 7 days’,
“For all three altered pre-freezing intervals, intraindividual variation (iCOV) was minimal (for samples stored for 7 days at room temperature; serum: 1.2%, plasma: 1.3%) and reproducibility close to perfect (for samples stored for 7 days at room temperature; serum: ICC = 0.99, plasma: ICC = 0.94).”
now reads:
“For all three altered pre-freezing intervals, intraindividual variation (iCOV) was minimal (for samples stored for 7 days at room temperature; serum: 9.0%, plasma: 6.5%) and reproducibility close to perfect (for samples stored for 7 days at room temperature; serum: ICC = 0.99, plasma: ICC = 0.94).”
Additionally, under the subheading ‘Inter‑assay variability’ of the Results section,
“For sNfL, the iSD was 0.6 pg/mL (range 0.5–1.2), the iCOV 0.1% (range 0.0–0.1) and the ICC 1.0 (range 0.99–1.00). For pNFL, the iSD was 1.6 pg/mL (range 0.8–2.7), the iCOV 0.1% (range 0.1–0.2) and the ICC 0.99 (range 0.90–1.00).”
now reads:
“For sNfL, the iSD was 0.6 pg/mL (range 0.5–1.2), the iCOV 4.8% (range 2.0–6.0) and the ICC 1.0 (range 0.99–1.00). For pNFL, the iSD was 1.6 pg/mL (range 0.8–2.7), the iCOV 12.7% (range 6.0–18.0) and the ICC 0.99 (range 0.90–1.00).”
Furthermore, Table 3 contained errors in the “iCOV (%)” columns for “Freezing intervals: 3 days RT”, “Freezing intervals: 3 days 4-8 °C” and “Freezing intervals: 7 days RT”.
The original Table 3 and accompanying legend appear below.
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 [pg/mL] | iCOV (%) | ICC | iSD [pg/mL] | iCOV (%) | ICC | iSD [pg/mL] | iCOV (%) | ICC | |
| (a) sNfL | |||||||||
| Whole cohort (and range) | 1.5 | 1.2 | 0.97 | 1.7 | 1.2 | 0.98 | 1.3 | 1.2 | 0.99 |
| 0.3–2.6 | 1.1–1.3 | 0.94–0.99 | 0.9–2.6 | 1.1–1.2 | 0.96–0.99 | 0.5–2.0 | 1.1–1.3 | 0.97–0.99 | |
| Lowest quartile (and range) | 0.5 | 1.2 | 0.90 | 0.4 | 1.2 | 0.91 | 0.5 | 1.2 | 0.90 |
| 0.1–0.9 | 1.0–1.3 | 0.65–0.94 | 0.2–0.6 | 1.2–1.3 | 0.66–0.94 | 0.1–0.8 | 1.1–1.4 | 0.64–0.93 | |
| Highest quartile (and range) | 3.4 | 1.2 | 0.92 | 4.3 | 1.2 | 0.94 | 2.7 | 1.2 | 0.95 |
| 1.5–8.4 | 1.0–1.4 | 0.60–0.98 | 1.2–7.3 | 1.0–1.3 | 0.69–0.99 | 0.5–5.9 | 1.1–1.4 | 0.78–0.99 | |
| (b) pNfL | |||||||||
| Whole cohort (and range) | 1.3 | 1.2 | 0.98 | 1.7 | 1.1 | 0.96 | 0.7 | 1.3 | 0.94 |
| 0.6–2.0 | 1.1–1.3 | 0.96–0.99 | 0.6–2.7 | 1.1–1.2 | 0.92–0.98 | 0.4–1.1 | 1.2–1.3 | 0.90–0.99 | |
| Lowest quartile (and range) | 0.4 | 1.2 | 0.90 | 0.6 | 1.1 | 0.90 | 0.5 | 1.2 | 0.88 |
| 0.2–0.6 | 1.1–1.3 | 0.61–0.92 | 0.2–1.0 | 0.9–1.3 | 0.60–0.93 | 0.3–0.7 | 1.1–1.3 | 0.59–0.91 | |
| Highest quartile (and range) | 3.4 | 1.2 | 0.91 | 4.5 | 1.1 | 0.86 | 1.7 | 1.3 | 0.84 |
| 0.6–6.2 | 1.0–1.3 | 0.53–0.98 | 0.2–9.0 | 0.9–1.4 | 0.27–0.98 | 0.1–3.3 | 1.1–1.4 | 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.
The original Article has been corrected.