The association between the CRP levels with age (p=0.03), gender (p=0.013), site of UTI (p=0.01), ultrasound findings (p=0.01), and the final diagnosis (p=0.02) of the patients in this study was significant (Table 3). The majority of the upper UTI patients diagnosed with acute pyelonephritis (30, 88.24%) had CRP >100 mg/L and lower UTI patients diagnosed with cystitis (22, 62.86%) had CRP levels between 3 and 50 mg/L (Table 3). This evidence concerns the gene CRP and acute pyelonephritis.