What to do if i have unine rbc count of 11-12 is it a serious disease?

Probably ok...?: Profile doesn't indicate if you are male or female, so I'm at a bit of a disadvantage. If you are female, some blood in the urine, especially in the absence of other symptoms, is common. In a male, it can mean lots of things (kidney stone, etc), most of which are not serious. It is important to know if you are having other symptoms. If not, I recommend getting a second urinalysis in 1-2 weeks.