LC-MS-MS Measurements of Urinary Creatinine and the Application of Creatinine Normalization Technique on Cotinine in Smokers’ 24 Hour Urine

Table 3

Correlation of 24 h urinary cotinine unadjusted and adjusted with tar.

Variable	𝑟
	8 mg : 10 mg	8 mg : 13 mg	10 mg : 13 mg
24 h cotinine concentration	0.716	0.808	0.822
Cotinine creatinine ratio	0.722	0.765	0.791