Can you have a kidney infection without obvious signs of a uti or fever?

Yes and No: Uti is an infection anywhere in the urinary tract and is verified by a positive culture. Most utis involve only the bladder/urethra (aka cystitis: urgency, frequency, burning). A more severe infection results when a UTI progresses to involve the kidneys/ureters (aka pyelonephritis: fever, chills, n/v, back pain, sick). Pyelo may or may not be associated with or preceded by cystitis symptoms.