Acid loading test (pH)
Renal tubular acidosis - acid loading testThe acid loading test (pH) measures the ability of the kidneys to send acid to the urine when there is too much acid in the blood. This test involves both a blood test and urine test.
How the Test is Performed
Before the test, you will need to take a medicine called ammonium chloride for 3 days. Follow instructions exactly on how to take it to ensure an accurate result.
Samples of urine and blood are then taken.
Urine
A clean catch is a method of collecting a urine sample to be tested. The clean-catch urine method is used to prevent germs from the penis or vagina ...
Blood
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
Your health care provider will tell you to take ammonium chloride capsules by mouth for 3 days before the test.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.
The urine test involves only normal urination, and there is no discomfort.
Why the Test is Performed
This test is done to see how well your kidneys control the body's acid-base balance.
Normal Results
Urine with a pH less than 5.3 is normal.
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
The most common disorder associated with an abnormal result is renal tubular acidosis.
Renal tubular acidosis
Proximal renal tubular acidosis is a disease that occurs when the kidneys don't properly remove acids from the blood into the urine. As a result, to...
Risks
There are no risks with providing a urine sample.
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
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Hematoma (blood accumulating under the skin)
Hematoma
A bruise is an area of skin discoloration. A bruise occurs when small blood vessels break and leak their contents into the soft tissue beneath the s...
ImageRead Article Now Book Mark Article - Infection (a slight risk any time the skin is broken)
References
Dixon BP. Renal tubular acidosis. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 547.
Seifter JL. Acid-base disorders. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 104.
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Female urinary tract - illustration
The female and male urinary tracts are relatively the same except for the length of the urethra.
Female urinary tract
illustration
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Male urinary tract - illustration
The male and female urinary tracts are relatively the same except for the length of the urethra.
Male urinary tract
illustration
-
Female urinary tract - illustration
The female and male urinary tracts are relatively the same except for the length of the urethra.
Female urinary tract
illustration
-
Male urinary tract - illustration
The male and female urinary tracts are relatively the same except for the length of the urethra.
Male urinary tract
illustration
Review Date: 12/31/2023
Reviewed By: Walead Latif, MD, Nephrologist and Clinical Associate Professor, Rutgers Medical School, Newark, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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