This is a medical question of type : exams and tests 
 How to diagnose Ectopic Kidney ? 
 A health care provider may use one or more of the following imaging tests to diagnose an ectopic kidney:
                
- Ultrasound. An ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. The procedure is performed in a health care providers office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologista doctor who specializes in medical imaging; anesthesia is not needed. The images can show the location of the kidneys.  - Intravenous pyelogram (IVP). An IVP is an x ray of the urinary tract. A special dye, called contrast medium, is injected into a vein in the persons arm, travels through the body to the kidneys, and makes urine visible on the x ray. The procedure is performed in a health care providers office, outpatient center, or hospital by an x-ray technician, and the images are interpreted by a radiologist; anesthesia is not needed. An IVP can show a blockage in the urinary tract. In children, ultrasounds are usually done instead of IVPs.  - Voiding cystourethrogram (VCUG). A VCUG is an x-ray image of the bladder and urethra taken while the bladder is full and during urination, also called voiding. The bladder and urethra are filled with contrast medium to make the structures clearly visible on the x-ray images. The x-ray machine captures images of the contrast medium while the bladder is full and when the person urinates. The procedure is performed in a health care providers office, outpatient center, or hospital by an x-ray technician supervised by a radiologist, who then interprets the images. Anesthesia is not needed, but sedation may be used for some people. The test can show abnormalities of the inside of the urethra and bladder and whether urine is backing up toward the kidneys during urination.  - Radionuclide scan. A radionuclide scan is an imaging technique that relies on the detection of small amounts of radiation after injection of radioactive chemicals. Because the dose of the radioactive chemicals is small, the risk of causing damage to cells is low. Special cameras and computers are used to create images of the radioactive chemicals as they pass through the kidneys. The procedure is performed in a health care providers office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologist; anesthesia is not needed. This test can show the location of an ectopic kidney and whether the ureters are blocked.  - Magnetic resonance imaging (MRI). MRI machines use radio waves and magnets to produce detailed pictures of the bodys internal organs and soft tissues without using x rays. An MRI may include the injection of contrast medium. With most MRI machines, the person lies on a table that slides into a tunnel-shaped device that may be open ended or closed at one end; some newer machines are designed to allow the person to lie in a more open space. The procedure is performed in an outpatient center or hospital by a specially trained technician, and the images are interpreted by a radiologist; anesthesia is not needed though light sedation may be used for people with a fear of confined spaces. MRIs can show the location of the kidneys.
                
In addition to imaging tests, blood tests may be done to determine how well the kidneys are working. These tests are almost always normal in people with an ectopic kidney, even if it is badly damaged, because the other kidney usually has completely normal function.