Hello and welcome to HCM,
Please ensure that the place where you urinated did not have oil deposit.
The rainbow like appearance is due to refraction
It is not any abnormality.
Ketones in urine produce a fruity odor rather than oily appearance.Ketone bodies
are present in urine in diabetics, during starvation
, in states of malnutrition
Flu will not cause ketone bodies in urine.
Thanks and take care
Dr Shailja P Wahal