When seeking to identify a patient’s health condition, advanced practice nurses can use a diverse selection of diagnostic tests and assessment tools; however, different factors affect the validity and reliability of the results produced by these tests or tools. Nurses must be aware of these factors in order to select the most appropriate test or tool and to accurately interpret the results.Not only do these diagnostic tests affect adults, but body measurements can also provide a general picture of whether a child is receiving adequate nutrition or is at risk for health issues. These data, however, are just one aspect to be considered. Lifestyle, family history, and culture—among other factors—are also relevant. That said, gathering and communicating this information can be a delicate process.