A test to see how much citric acid is in your urine is used to help evaluate your risk for kidney stones or to help diagnose other health conditions. Low levels of citric acid are risk factors for kidney stones, but higher levels may have a protective effect. You can influence the amount of citric acid in your urine through your diet. Always discuss possible dietary changes and any test results with your doctor.
A citric acid urine test is performed over a 24-hour period. The normal range of citric acid in your urine is 320 to 1,240 mg in 24 hours. However, ranges for normal results can vary among laboratories, so it's important to have a doctor analyze your readings, according to MedlinePlus. There's no discomfort when you take a citric acid urine test because it simply involves urinating normally and collecting your urine in a special container. Because test results are influenced by your diet, you need to eat normally when you take the test.
If your urine citric acid levels are low, you may have a tendency to form kidney stones. Citric acid has a protective effect against kidney stones – the more you have in your urine, the more protected you are. In its natural form, such as from fruit, citric acid in your urine prevents kidney stones from getting bigger by coating them. This keeps other material from attaching to the stones and building onto them. Citric acid also may break up small stones that are starting to form and inhibits new stone formation.
Renal Tubular Acidosis
Low citric acid levels are an indicator of renal tubular acidosis. This is a condition in which your kidneys don't remove acids in your urine properly. This leaves your blood too acidic. Your kidneys play an important role in regulating your body's acid-base balance, or pH. Symptoms of acidosis include fatigue, dehydration, weakness, muscle pain, decreased urine output, muscle cramps and an irregular or increased heart rate. This condition is treated with alkaline medications such as potassium citrate and sodium bicarbonate.
Other factors may decrease the level of citric acid in your urine. These include chronic kidney failure, diabetes, excessive muscle activity and hypoparathyroidism, an endocrine disorder in which your parathyroid glands don't produce adequate parathyroid hormone. These glands help regulate calcium removal and use in your body. Factors that can raise citric acid levels in your urine include eating a high-carbohydrate diet, vitamin D and estrogen therapy.
You can raise your urine levels of citric acid by consuming fruits and fruit juices that contain citric acid. The best food sources of citric acid are lemons and limes. In fact, 4 oz. of pure lemon juice or 32 oz. of lemonade daily give you the same amount of citric acid that pharmacological therapy used for kidney stones does. Although other citrus fruits don't contain as much citric acid as lemons and limes, foods such as oranges and grapefruit also add to your citric acid intake.