Which method is a common initial investigation for diagnosing a UTI in a child with dysuria and fever?

The common initial investigation for diagnosing a urinary tract infection (UTI) in a child presenting with dysuria (painful urination) and fever is a clean catch urine analysis. This method is favored as it provides a reliable sample for testing while minimizing contamination from the surrounding skin and genital area.

In pediatric patients, obtaining urine samples can be challenging, and the clean catch method strikes a balance between convenience and accuracy. It requires the child to urinate into a sterile container, which can help in yielding a sample that reflects the urinary status accurately.

Other methods, such as urine dipstick tests, may offer preliminary information but are not definitive. They can indicate the presence of substances like nitrates or leukocyte esterase that suggest infection, yet they require confirmation through culture. Blood cultures are more invasive and not typically the first step in diagnosing a UTI in children unless there are signs of systemic infection. Imaging studies like X-rays are not indicated for initial diagnosis and are reserved for specific clinical scenarios when structural anomalies are suspected following recurrent UTIs.

Thus, a clean catch urine analysis is the most appropriate and commonly used method for diagnosing UTIs in children presenting with the mentioned symptoms.