What drugs are used and how depend on your overall health and the bacteria in your urine. Cystitis caused by a bacterial infection is usually treated with antibiotics. Treatment for noninfectious cystitis depends on the underlying cause. First infection. Symptoms often improve significantly within a day or so of antibiotic treatment. However, you will likely need to take antibiotics for three days to a week, depending on the severity of the infections. TESTS AND DIAGNOSIS When cystitis is suspected, the doctor first examines the person's abdomen and lower back to evaluate for unusual enlargements of the kidneys. or swelling of the bladder. Tests that the doctor may prescribe: Urinalysis. It is used to determine whether bacteria, blood or pus are present in the urine. Cystoscopy. Use to remove a small sample of tissue (biopsy) for analysis in the laboratory. This test will most likely not be necessary if this is the first time the patient has had signs or symptoms of cystitis. (Continued) Imaging tests. Imaging tests are usually not necessary, but in some cases, especially when no evidence of infection is found, they may be helpful. For example, an x-ray or ultrasound can help pinpoint other potential causes of inflammation, such as a tumor or structure