Hi thanks for asking question. You gave not mentioned age of your child. During fever as less water drinking she might have dehydration and kidney function test comes abnormal.. To look for kidney disease like pyelonephritis , stones or glomerulonephritis USG can be done.... If kidney disease there causative treatment done... If cause not clear and urine show proteinuria then for further work up if needed biopsy might needed. Take care... If she developed any unusual sign and symptom consult doctor for it...