Will a cbc w/o differential show if something is wrong with my kidneys? thanks

No: The CBC checks your white blood cells, red cells, and platelets. People with kidney disease frequently have anemia (low red cell counts), but the CBC is not a kidney test. Bun, creatinine, and urine analysis would be a good starting point to evaluate for kidney problems.

CBC & renal disease: If you are talking about chronic kidney disease (ckd), a person may have an unexplained anemia. This is usually seen in patients in class 4 CKD and at times class 3. A metabolic panel that would reveal your creatinine, BUN as well as other serum electrolytes would be better. See a doctor to get that blood work done.