PrintIn Whitaker test, a contrast dye is injected directly into one of your kidneys, and a series of x-ray films is taken as the material flows through the kidney and ureter. The dye delineates these structures on the x-ray images and reveals any abnormalities. Pressures are also measured in the kidneys and bladder. Correlation of the pressure measurements with the x-ray findings can provide information about the flow of urine through the kidney and the presence of any obstructions.
Purpose of the Whitaker Test
- To identify and evaluate kidney obstructions (such as narrowing or stones)
- To help determine whether surgery is needed to remove a kidney obstruction
Who Performs the Whitaker Test
- A physician, usually an interventional radiologist
Special Concerns about the Whitaker Test
- People who have an allergy to shellfish or iodine may experience an allergic reaction to the contrast dye.
- Pregnant women should not undergo this test because exposure to ionizing radiation may harm the fetus.
- This test may not be safe for people who have a bleeding disorder or a severe infection.
- The presence of feces, gas or residual barium in the abdomen from recent contrast x-rays may hinder accurate needle placement and interfere with visualization of the upper urinary tract.
Before the Whitaker Test
- Tell your doctor if you regularly take anticoagulant drugs. You may be instructed to discontinue them for some time before the test.
- Be sure to tell your doctor if you have a known shellfish or iodine allergy or have ever had an adverse reaction to x-ray contrast dyes.
- Do not eat or drink anything for at least 4 hours before the test.
- You will be asked to disrobe and put on a hospital gown.
- You may be given a mild sedative.
- You may be asked to empty your bladder just before the procedure.
What You Experience During the Whitaker Test
- You will lie on your back on an examination table.
- A thin tube, or catheter, equipped with a special pressure sensor is gently inserted through the urethra into the bladder.
- The doctor takes a plain x-ray film of the urinary tract to locate the position of the kidney and ureter.
- A contrast dye is administered through an intravenous (IV) catheter inserted into a vein in your arm. (Upon injection of the dye, you may experience a brief flushing sensation and a metallic taste in your mouth.)
- When x-rays show that the contrast dye has entered the kidney, the skin over the kidney is cleansed with an antiseptic solution and draped. A local anesthetic is then injected to numb the area.
- You will be asked to hold your breath as the doctor inserts a hollow needle into your kidney, using fluoroscopy or ultrasound imaging as a guide. A pressure sensor is connected to this needle.
- Contrast dye is infused through the needle into your kidney, and serial x-ray films are obtained to visualize the kidney and ureter. You should remain still as each x-ray is taken.
- Pressures within the kidney and bladder are measured.
- The needle and catheter are then removed, and a small bandage is applied over the needle insertion site.
- The test takes about 60 to 90 minutes.
Risks and Complications of the Whitaker Test
- X-rays involve minimal exposure to radiation.
- Possible complications include bleeding at the site of needle insertion.
- Some people may experience an allergic reaction to the iodine-based contrast dye, which can cause symptoms such as nausea, sneezing, vomiting, hives, and occasionally a life-threatening response called anaphylactic shock. Emergency medications and equipment are kept readily available.
After the Whitaker Test
- A pressure dressing is applied to the site of needle insertion.
- You will rest in a recovery room for 15 to 30 minutes. Your vital signs will be monitored, and pain medication will be provided if necessary.
- If no complications develop, you are usually free to leave the testing facility. You will be advised to remain on your back for 12 hours after the test.
- You will be instructed to keep track of your urine output and report any urinary retention (inability to urinate due to swelling). At first, the urine may contain blood, causing a slight pink tinge; this should resolve after voiding a few times. If blood persists or you see bright red blood or blood clots, notify your physician.
- You may resume your normal diet and any medications withheld before the test.
- Delayed allergic reactions to the contrast dye, such as hives, rash, or itching, may appear 2 to 6 hours after the procedure. If this occurs, your doctor will prescribe antihistamines or steroids to ease your discomfort.
- You may be given prophylactic antibiotic drugs for several days to prevent infection.
- Report to your doctor any signs of infection, such as chills, fever rapid breathing, or a feeling of faintness.
Results of the Whitaker Test
- The doctor will examine the x-rays and pressure measurements to determine whether a kidney obstruction is present.
- A definitive diagnosis can usually be made after this test. Appropriate treatment will be initiated, depending on the specific problem.
Source:
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media
