Is it possible for a 55 years old lady to still have uti when urine test report is all clear with no abnormal readings at all?

Possible: Have you had an urine culture? Urine culture of properly obtained specimen can provide a definite answer.

What test ?: I can think of at least a dozen tests I can do on urine . The definitive test for a UTI would be a culture done on a clean catch or catheterized specimen. If they just looked at a sample or did a simple dipstick strip test it is less conclusive but usually will show signs. You can also have symptoms similar to a UTI form other issues.