We collected 56 intraday urine samples from pediatric SJIA patients at two sites, Stanford and UCSF (Tables 1, 2, and 3). These included patients with ND (n=2), SAF (n=18), AF (n=9), SJIA quiescence (inactive disease on medication; QOM, n=18), SJIA remission (inactive disease off all medications) (RD, n=9). For comparison, samples from subjects with KD (n=23), and acute FI (n=23) ( Table 2; collected at UCSD), and healthy, age-matched controls (HC, n=10, collected at Stanford) were collected.