A urine pH test measures the acidity of urine.
See also: Acid loading test
pH - urine
Why the pH - urine is Performed
This test measures how acidic your urine is.
Your provider may want to test your urine pH to see if you are risk for kidney stones. Acidic urine is associated with xanthine, cystine, uric acid, and calcium oxalate stones. Alkaline urine is associated with calcium carbonate, calcium phosphate, and magnesium phosphate stones.
Your doctor may also order this test if you need to take certain medications. Some medications are more effective in acidic or alkaline environments. For example, streptomycin, neomycin, and kanamycin are more effective in treating urinary tract infections when the urine is alkaline.
How the pH - urine is Performed
To obtain a clean-catch urine sample, boys and men should wipe the head of the penis clean. Girls and women need to wipe between the vagina "lips" (labia) with soapy water and rinse well. Your doctor may give you a special clean-catch kit that contains a cleansing solution and sterile wipes.
To perform this test, first urinate a small amount into the toilet bowl to clear the urethra of any contaminants. Then, collect a sample of urine in a clean or sterile container. About 1 - 2 ounces of urine is needed for a test. Remove the container from the urine stream without stopping the flow. You may finish urinating into the toilet bowl. Take the sample to the lab.
For infants, the genital area is cleaned and dried, and then a collection device is attached to collect the urine. If you are asked to collect the urine, be sure the collection device is attached securely to prevent leakage. After your baby has urinated, the urine (at least 20 cc) is placed in a sterile container.
How to Prepare for the pH - urine
Your health care provider may tell you to stop taking certain drugs that can affect the results of the test.
- Drugs that increase urine pH include acetazolamide, potassium citrate, and sodium bicarbonate.
- Drugs that can decrease urine pH include ammonium chloride, chlorothiazide diuretics, and methenamine mandelate.
Eat a normal, balanced diet for several days before the test.
- A diet high in citrus fruits, vegetables, or dairy products can increase your urine pH.
- A diet high in meat products or cranberries can decrease your urine pH.
How the pH - urine Will Feel
The test involves only normal urination, and there is no discomfort.
There are no risks.
Urine pH can be affected by various factors after collection such as leaving the urine standing in an uncovered container. Bacteria usually increase the pH as they break down urea in the urine to ammonia.
The normal values range from 4.6 to 8.0.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
A high urine pH may be due to:
- Gastric suction
- Kidney failure
- Kidney tubular acidosis
- Urinary tract infection
A low urine pH may be due to:
- Chronic obstructive pulmonary disease (such as emphysema)
- Diabetic ketoacidosis
The test also may be performed to investigate:
- Interstitial nephritis
- Kidney tubular acidosis - distal