From: Relation of 24-hour urinary caffeine and caffeine metabolite excretions with self-reported consumption of coffee and other caffeinated beverages in the general population
Sensitivity
Specificity
Cutoff (mg)
24-h urinary metabolite
24-h urinary caffeine
0.723
0.840
1.391
24-h urinary paraxanthine
0.801
0.790
2.582
24-h urinary theophylline
0.787
0.800
0.774
24-h urinary theobromine
0.938
0.160
1.665