What are the possible causes of less urine.cretanine is 0.9 and bun 10.9 and calcium 8.64.do one need to worry!!

Go see your MD: Schedule a visit with your physician to have your electrolytes checked. Normal BUN levels vary from 7-20. Dehydration and several factors raise the BUN and overhydration &oth causes decrease BUN. Your doctor needs a thorough history and physical, meds, etc. When one is hydrated the urine is clear. Dehydration causes dark yellow urine. Your creatinine appears normal and reflects kidney function.

By "less urine": I presume you mean a reduced volume of urine being voided. The most common cause of this is dehydration...too little fluid intake so the volume of blood falls; less blood to the kidneys for urine production. Typically this would result in creatinine and BUN being elevated; yours are low, but normal, as is the calcium.This could all be ok, especially if you are drinking enough. Further ?'s, see Doc