What type of examination is crucial for diagnosing urinary tract infections?

The correct answer is urinalysis, which is essential for diagnosing urinary tract infections (UTIs). This diagnostic test analyzes the urine for various indicators that can suggest an infection, such as the presence of white blood cells, red blood cells, bacteria, and nitrates. A urinalysis can often be performed quickly and provides immediate insight into a patient's urinary health, allowing healthcare providers to identify a UTI efficiently.

In the context of diagnosing UTIs, blood cultures are primarily used to detect bacteria in the bloodstream rather than in the urinary system, making them less relevant for this condition. X-ray imaging is generally employed for assessing structural abnormalities or complications but does not provide specific information regarding infections. Similarly, a CT scan can help visualize urinary tract structures and conditions, but it is not the first-line test for diagnosing a simple UTI. Thus, urinalysis remains the most critical and specific examination for this purpose.