What is the purpose of a urine culture?

• A. Identify causative organism and determine antibiotic susceptibility
• B. Detect proteinuria
• C. Measure urine osmolarity
• D. Assess urine pH only

Answer: (A)

A urine culture is used to isolate the bacteria in the urine and determine which antibiotics will be effective against that organism. This lets clinicians identify the causative microbe and tailor therapy to what will actually work, which is crucial for treating infections and avoiding unnecessary broad-spectrum antibiotics.

Other urine tests—like those that detect protein, measure osmolarity, or assess pH—provide information about kidney health, hydration status, or metabolic conditions, but they do not identify the organism responsible for an infection or guide antibiotic selection. In a culture, after collecting a sterile urine sample, the specimen is grown on culture media; if bacteria appear, they are identified and tested against a panel of antibiotics to determine susceptibility, directing targeted treatment.