The acid loading test (pH) measures the ability of the kidneys to send acid to your urine when there is too much acid in your blood.
See also: Urine pH
You will be told to take ammonium chloride capsules by mouth for 3 days. Then, a urine and blood sample are taken. The laboratory measures the level of acid found in both samples.
For information on how the urine and blood samples are obtained, see:
Your doctor will tell you to take ammonium chloride capsules by mouth for 3 days prior to the test.
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
This test is done to see how well your kidneys control the body's acid-base status.
Urine with a pH less than 5.3 is normal.
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 doctor about the meaning of your specific test results.
The most common disorder associated with an abnormal result is renal tubular acidosis.
There are no risks associated with providing a urine sample.
The risks of having blood drawn include:
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Seifter JL. Acid-base disorders.In: Goldman L, Schafer AI, eds.Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 120.