Had ultrasound done on abdomen report said unremarkable liver gallbladder and spleen but said my right kidney was slightly small measured size kidney.

Likely insignificant: The renal length varies with height and weight and decreases slowly with age. Right kidney is usually slightly smaller than the Left. Normal size ranges from 9-12 cm (90-120 mm) and the difference in size should not exceed 2 cm. So the right kidney being "slightly" smaller is likely insignificant. If you have the actual measurements you can interpret them using the above guidelines.