Table 2.

Measurement uncertainty calculation results

Calculation interval	Number of replicate series in 0–5-FNU range	Reproducibility within-laboratory uRw (FNU)	Method and laboratory bias ub (FNU)	Expanded measurement uncertainty for the 0–5-FNU range expressed in FNU (k = 2)	Number of replicate series in 5–40-FNU range	Reproducibility within-laboratory uRw% (%)	Method and laboratory bias ub (%)	Expanded measurement uncertainty for the 5–40-FNU range expressed in % (k = 2)
1-week calculation intervals
23 Jan–30 Jan 2018	48	0.22	0.34	0.81	103	7.4	6.7	19.9
30 Jan–6 Feb 2018	50	0.57	0.15	1.18	111	6.2	11.7	26.4
6 Feb–13 Feb 2018	23	0.41	0.088	0.83	138	5.0	2.7	11.2
13 Feb–22 Feb 2018	143	0.79	0.16	1.62	52	5.2	2.9	11.9
2-week calculation intervals
23 Jan–7 Feb 2018	104	0.49	0.15	1.02	230	8.1	7.9	22.5
7 Feb–22 Feb 2018	160	0.65	0.13	1.33	174	5.1	2.6	11.3
1-month calculation interval
23 Jan–22 Feb 2018	264	0.57	0.12	1.2	404	7.9	4.9	18.6