Table 2.

Spearman’s rs rank-order correlation matrix between all nine serum markers

	Biomarker correlations
	IgA	IgG	IgM	CRP	Albumin	Haptoglobin	WBC	Iron	TIBC
IgA	1.00	0.22 P < 0.0001	− 0.07 P < 0.0001	0.11 P < 0.0001	− 0.26 P < 0.0001	0.16 P < 0.0001	0.05 P < 0.0001	− 0.01 P = 0.4639	− 0.11 P < 0.0001
IgG	0.22 P < 0.0001	1.00	0.13 P < 0.0001	0.07 P < 0.0001	− 0.20 P < 0.0001	0.02 P = 0.1536	− 0.03 P = 0.0184	− 0.01 P = 0.5675	− 0.07 P < 0.0001
IgM	− 0.07 P < 0.0001	0.13 P < 0.0001	1.00	0.02 P = 0.0972	− 0.06 P < 0.0001	− 0.04 P = 0.0034	− 0.01 P = 0.2745	− 0.01 P = 0.2809	− 0.01 P = 0.4373
CRP	0.11 P < 0.0001	0.07 P < 0.0001	0.02 P = 0.0972	1.00	− 0.29 P < 0.0001	0.50 P < 0.0001	0.17 P < 0.0001	− 0.28 P < 0.0001	− 0.11 P < 0.0001
Albumin	− 0.26 P < 0.0001	− 0.20 P < 0.0001	− 0.06 P < 0.0001	− 0.29 P < 0.0001	1.00	− 0.31 P < 0.0001	− 0.08 P < 0.0001	0.14 P < 0.0001	0.19 P < 0.0001
Haptoglobin	0.16 P < 0.0001	0.02 P = 0.1536	− 0.04 P = 0.0034	0.50 P < 0.0001	− 0.31 P < 0.0001	1.00	0.25 P < 0.0001	− 0.25 P < 0.0001	− 0.01 P = 0.2710
WBC	0.05 P < 0.0001	− 0.03 P = 0.0184	− 0.01 P 0.2745	0.17 P < 0.0001	− 0.08 P < 0.0001	0.25 P < 0.0001	1.00	− 0.09 P < 0.0001	0.02 P = 0.0717
Iron	− 0.01 P = 0.4639	− 0.01 P = 0.5675	− 0.01 P = 0.2809	− 0.28 P < 0.0001	0.14 P < 0.0001	− 0.25 P < 0.0001	− 0.09 P < 0.0001	1.00	− 0.06 P < 0.0001
TIBC	− 0.11 P < 0.0001	− 0.07 P < 0.0001	0.01 P = 0.4373	− 0.11 P < 0.0001	0.19 P < 0.0001	− 0.01 P = 0.2710	0.02 PP = 0.0717	− 0.06 P < 0.0001	1.00

Correlations above or equal to ± 0.25 are in bold. All these correlations are statistically significant (P value < 0.0006)

WBC white blood cells, TIBC total iron-binding capacity