Best procedure before ordering a radiologic study with contrast?

How much of a workup do you recommend before ordering diagnostics with contrast (assuming kidney function tests are normal)? Is a basic metabolic panel enough? — Sharon Owens, NP, Salisbury, Md.

Specifically, kidney function tests need to be evaluated prior to ordering a radiologic study with contrast. While a basic metabolic panel is an acceptable option, the results of creatinine and blood urea nitrogen levels are what are needed (electrolytes are not necessary).

Contrast is metabolized through — and can be toxic to — the kidneys. This is especially important to consider in the elderly, as age-related decline in kidney function can be asymptomatic. Radiologic contrast is useful when cancer is one of the differential disgnoses. — Rebecca H. Bryan, APRN, CNP (159-4)