To discover an SJIA systemic flare signature, the urine spectra of the subjects with systemically active disease, SJIA ND (n=2), and SAF (n=18) patients, were compared simultaneously to the non-systemic group of SJIA AF (n=9) and the QOM (n=18) patients and the other systemic inflammation groups: KD (n=23) and FI (n=23). The data mining process included selection of the discriminative urine "Bootstrapping" differing from in silico bootstrapping (re-sampling) simulation, samples belonging to different visits of the same patient and even the same samples were assayed, i.e.