Table 2.

Correlation coefficient matrix between osmolality and other laboratory tests

	Serum osmolality	CSF osmolality	Δ-Osmolality
Serum osmolality	–	0.917***	−0.144
		(0.880–0.943)	(−0.327–0.049)
CSF osmolality	–	–	0.262**
			(0.074–0.432)
Age	0.244*	0.183	−0.148
	(0.049–0.421)	(−0.015–0.367)	(−0.335–0.051)
Serum Na+	0.648***	0.709***	0.096
	(0.501–0.758)	(0.582–0.803)	(−0.124–0.307)
Serum K+	0.151	0.017	−0.295*
	(−0.099–0.383)	(−0.230–0.262)	(−0.504– −0.052)
Serum Cl–	0.421***	0.527***	0.187
	(0.196–0.604)	(0.323–0.684)	(−0.061–0.413)
CSF Cl–	0.713***	0.786***	0.122
	(0.570–0.813)	(0.673–0.863)	(−0.122–0.351)
Serum TP	0.237	0.194	−0.105
	(−0.020–0.465)	(−0.065–0.429)	(−0.351–0.155)
CSF TP	−0.229	−0.322**	−0.199
	(−0.437–0.002)	(−0.514– −0.098)	(−0.411–0.034)
QAlb	−0.102	−0.192	−0.175
	(−0.351–0.160)	(−0.429–0.070)	(−0.415–0.087)
CSF-CC	−0.001	−0.069	−0.142
	(−0.225–0.223)	(−0.288–0.157)	(−0.355–0.084)
IgG-index	−0.139	−0.231	−0.099
	(−0.413–0.158)	(−0.489–0.064)	(−0.379–0.198)

A list of Pearson’s correlation coefficients (r) with the 99% confidence intervals. Δ-Osmolality is the difference of osmolality between CSF and venous blood. Δ(TP-Alb) is the difference between the serum total protein level and the serum albumin level. CSF: Cerebrospinal fluid; CSF-CC: cell count in the cerebrospinal fluid; IgG: immunoglobulin G; QAlb: quotient of albumin; QIgG: quotient of immunoglobulin G; TP: total protein. *P < 0.01, **P < 0.001, ***P < 0.0001.