Many kidney problems can be diagnosed with blood and urine tests. One of these tests measures creatinine in the blood. The rate at which the kidneys clear wastes, known as the glomerular filtration rate or GFR, can be estimated from blood creatinine. If you have a long-term or progressive kidney disorder, you should ask your kidney specialist about your GFR.
Nephrologists rely on a number of studies to examine the size, position, and structure of the kidneys:
- Ultrasound is the most common test ordered. It can demonstrate kidney size, position, dilatation, echotexture, and other abnormalities. With Doppler flow studies, the size and flow through the kidney vessels can also be assessed.
- Voiding cystourethrogram (VCUG) involves placing a catheter in the bladder, filler the bladder with a dye, and taking pictures as the patient voids. This study can diagnose vesicoureteral reflux, abnormalities of the bladder, and blockage in the urethra such as posterior urethral valves.
- Nuclear scans use a small amount of a radioactive tracer to demonstrate blood flow and function of the kidneys. Some can demonstrate small scars; others provide the best indication of obstruction the the rest of the urinary tract.
- CT scanning provides the most sensitive study for the detection of kidney stones.
The ultimate test we perform is a kidney biopsy. For this study, a special needle is placed in one kidney and pieces are removed for laboratory evaluation. Information for patients and their parents can be downloaded and printed at the Information Page.