Urine pH test

Definition

A urine pH test measures the level of acid in urine.

Alternative Names

pH - urine

How the Test is Performed

After you provide a urine sample, it is tested right away. The health care provider uses a dipstick made with a color-sensitive pad. The color change on the dipstick tells the provider the level of acid in your urine.

How to Prepare for the Test

Your provider may tell you to stop taking certain medicines that can affect the results of the test. These may include:

• Acetazolamide
• Ammonium chloride
• Methenamine mandelate
• Potassium citrate
• Sodium bicarbonate
• Thiazide diuretic

DO NOT stop taking any medicine before talking to your provider.

Eat a normal, balanced diet for several days before the test. Note that:

• A diet high in fruits, vegetables, or non-cheese dairy products can increase your urine pH.
• A diet high in fish, meat products, or cheese can decrease your urine pH.

How the Test will Feel

The test involves only normal urination. There is no discomfort.

Why the Test is Performed

Your provider may order this test to check for changes in your urine acid levels. It may be done to see if you:

• Are at risk of kidney stones. Different types of stones can form depending on how acidic your urine is.
• Have a metabolic condition, such as renal tubular acidosis.
• Need to take certain medicines to treat urinary tract infections. Some medicines are more effective when urine is acidic or non-acidic (alkaline).

Normal Results

The normal values range from pH 4.6 to 8.0.

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

A high urine pH may be due to:

• Kidneys that do not properly remove acids (kidney tubular acidosis, also known as renal tubular acidosis)
• Kidney failure
• Stomach pumping (gastric suction)
• Urinary tract infection
• Vomiting

A low urine pH may be due to:

• Diabetic ketoacidosis
• Diarrhea
• Too much acid in the body fluids (metabolic acidosis), such as diabetic ketoacidosis
• Starvation

Risks

There are no risks with this test.

References

Bushinsky DA. Kidney stones. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 32.

DuBose TD. Disorders of acid-base balance. In: Skorecki K, Chertow GM, Marsden PA, Taal MW, Yu ASL, eds. Brenner and Rector's The Kidney. 10th ed. Philadelphia, PA: Elsevier; 2016:chap 17.

Fogazzi GB, Garigali G. Urinalysis. In: Feehally J, Floege J, Tonelli M, Johnson RJ, eds. Comprehensive Clinical Nephrology. 6th ed. Philadelphia, PA: Elsevier; 2019:chap 4.

Riley RS, McPherson RA. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 28.