<prompt> A boy is suffering from acute pyelonephritis. Most specific urinary finnding will be:WBC castLeucocyte esterase testNitrite testBacteria in Gram stain  <response>: Sensitivity and Specificity of Urinanalysis in UTI: Tests Sensitivity Specificity Esterase 83 67-94 7864-92 Nitrite 5315-82 9890-100 Esterase or NItrite 9390-100 7258-91 White blood cells 7332-100 8145-98 Bacteria 8116-99 8311-100 Any above 99.8 99-100 7060-92 Ref: Smith 18th edition Pgno: 200 