Table 4.

Correlation between protein biomarker abundances in blood samples and physical tests

Target	Clinical parameter	LUMC serum			UCL serum			UNEW serum			UCL plasma
		Samples	ρ	P-value	Samples	ρ	P-value	Samples	ρ	P-value	Samples	ρ	P-value
CK	NSAA score	25	0.56	0.004	22	–0.54	0.009	45	0.31	0.037	24	–0.65	6.0e-04
ETFA	NSAA score	25	0.71	7.1e-05	22	–0.53	0.012	45	0.50	5.0e-04	30	–0.40	0.05
	6MWD	34	0.49	0.003	26	0.66	3.0e-04	ND	ND	ND	24	0.64	1.4e-04
MDH2	NSAA score	25	0.70	9.5e-05	22	–0.50	0.017	45	0.56	6.3e-05	24	–0.40	0.06
	10MWT	45	–0.52	3.0e-04	16	–0.54	0.032	ND	ND	ND	18	–0.41	0.09
	6MWD	34	0.47	0.005	26	0.62	8.0e-04	ND	ND	ND	30	0.50	0.005

Spearman rank correlation coefficient ρ was calculated for each protein biomarker per sample collection. Biomarkers correlating with outcome of physical tests as NSAA score, 6MWD and 10MWT with ρ > 0.50 or ρ<–0.50 in at least 2 sample collections and P-values < 0.05 were included.