Urine pH can be an important indicator of overall health and testing can be used to reveal a number of health problems. Some of the problems that unusually high or low urine pH values may indicate include urinary tract infection, kidney problems, and a tendency toward kidney stones. Abnormal urine pH values may also be caused by a vegetarian diet, starvation, dehydration, and certain drugs. In addition to indicating health problems, urine pH is helpful in determining how well certain medications will work. Doctors may order a urine pH test before prescribing medications that are more effective within a certain pH range.
Generally, the pH values of urine range from 4.6 to 8.0. A pH value of 7.0 is considered neutral, while greater values indicate alkaline urine, and lesser values indicate acidic urine. Urine that is alkaline or acidic may serve as insight to certain things that are going on inside the body.
Alkaline urine may be caused by kidney failure, vomiting, or urinary tract infection. It may also indicate that the kidneys are not properly removing acids from the urine — a condition known as proximal renal tubular acidosis. Having alkaline urine, however, does not always indicate a serious health problem. It could simply be a reflection of a vegetarian diet or taking alkalizing drugs, such as potassium citrate, acetazolamide, and sodium bicarbonate.
Acidic urine may be the result of diarrhea, diabetic ketoacidosis, chronic obstructive pulmonary disease (COPD), or starvation. It may also be caused by certain medications, such as chlorothiazide diuretics, ammonium chloride, and methenamine mandelate. Diets high in meats or cranberries may also lower urine pH enough to make it acidic.
Both alkaline and acidic urine could indicate a predisposition to kidney stones. Xanthine, cystine, uric acid, and calcium oxalate stones tend to form in acidic urine, while calcium carbonate, calcium phosphate, and magnesium phosphate stones tend to form in alkaline urine. A urine pH test is a helpful tool in preventing kidney stones. If a test reveals that a person is at risk, he or she may be prescribed a special diet to change the pH of his or her urine.
Bringing health problems to attention, increasing the efficacy of medications, and preventing kidney stones are all benefits that may result from a urine pH test. To prepare for a urine pH test, a person usually should avoid taking drugs or eating excessive amounts of certain foods that could skew the results. A balanced diet typically should be consumed from a variety of sources.
Also, a person should avoid giving a urine sample shortly after waking up. Breathing decreases during sleep, thereby causing respiratory acidosis. This, in turn, causes urine samples taken upon waking to be highly acidic.