MAG3/DTPA Renal Scintigraphy can determine overall renal (kidney) function and also relative left and right kidney function. The test is performed using the radiotracer called Tc99m-DTPA (Diethylene Triamine Pentacaetic Acid) or Tc99m-MAG3 (Mercaptoacetyltriglycine). The test is often used in combination with a diuretic drug such as frusemide to determine if a kidney is obstructed. The scan can also be very useful in assessing the function of renal transplant grafts.