What is Urine pH?

Urine pH reflects the body's metabolic activity. Measuring it allows doctors to easily diagnose and follow-up on different disorders.
What is Urine pH?
Karina Valeria Atchian

Written and verified by the doctor Karina Valeria Atchian.

Last update: 25 August, 2022

Urine samples are a simple way for doctors to test the health of your kidneys and other parts of the body. Also, some other things they study are the hydrogen potential, or urine pH.

Since ancient Greece, urine has been a diagnostic method. Color, turbidity, odor, volume, viscosity, and even sweetness have been measured. Then, from the invention of the microscope in the seventeenth century, specialists started studying urinary sediment. Finally, it was added as a routine study method for medical check-ups.

Nowadays, urine tests are an accessible, inexpensive, non-invasive, and easily collected study that allows us to check for various conditions. For example, one of the parameters that urinary samples study is urine pH.

The kidney functions normally thanks to multiple cellular processes. Also, if any of these functions are disturbed, it may threaten your health.

We’ll start with some general concepts to understand urine pH better.

What is urinalysis for?

As we have mentioned, urinalysis is a non-invasive study method. In addition, it fulfills lots of functions to detect and monitor different conditions:

  • Monitor the evolution of known kidney disease
  • Diagnose acute or chronic kidney disease in patients with other suspected symptoms
  • Find kidney diseases in a patient without apparent symptoms
  • General disease marker
Urine samples for an analysis.

What parameters of urine are studied?

In a urinalysis, various parameters can be studied, including the following:

  • Glomerular filtration rate: The main measure of kidney function
  • Urinary sediment: Erythrocytes, leukocytes, casts, and crystals in urine
  • Proteinuria: Abnormal elimination of protein in the urine
  • Urine pH
  • Changes in urinary volume: Oliguria, anuria, polyuria
  • The presence of glucose in urine
  • Electrolyte abnormalities: Sodium, chloride, potassium, calcium

What is urine pH?

This concept refers to the concentration of hydrogen ions in urine. Also, it reflects the degree of acidity. Its normal value is between 4.5 and 8.

Additionally, the complex system that regulates blood pH is made up of three parts that work at the same time:

  • Kidneys
  • Lungs
  • A chemical buffer system

The way that kidneys contribute to the balance of the pH in the blood is through the elimination or retention of urine. Also, it can be either acidic or alkaline substances, depending on what your body needs. However, the goal is always to keep the blood’s pH at a healthy level, around 7.4.

Here, we can classify urine ph into three grades:

  • Acidic urinary pH when the value is low: less than 5.5.
  • Alkaline urinary pH when it’s high: above 7.
  • If the pH is 7, it’s neutral.

Whenever there’s a different pH, specialists should consider the patient’s blood and medical history. In addition, they should look at renal function, the presence or absence of urinary infections, diet, and other factors.

Different colors on a urine test.

Check this out: Understand Your Metabolism to Effectively Lose Weight

The causes of acidic urine

There’s a long list of causes that cause acidic urine. For example, some of these are:

  • Chronic obstructive pulmonary disease or emphysema
  • Diabetes mellitus
  • Starvation
  • Dehydration
  • Diarrhea
  • Presence of acid-producing bacteria, like Escherichia coli.
  • High protein diet
  • Cranberry juice
  • Medications

The causes of alkaline urine

On the other hand, the possible causes of alkaline urine are:

  • Hyperventilation
  • Vomiting
  • Renal tubercular acidosis
  • Presence of urease-producing bacteria
  • Vegetarian diet
  • Old samples

What’s the ideal urine sample?

Generally, the first urine in the morning is the best sample for a urine test. Usually, it’s a concentrated sample that guarantees the detection of chemicals and elements that you might not find in a random sample.

Then, after collection, you should bring it to a lab right away for analysis. However, if you can’t deliver it right away, you should refrigerate it between 25-46ºF. This way, you can avoid bacterial growth and metabolism of the sample. In addition, it won’t change the pH of the sample.

The importance of measuring urine pH

Studying urine samples is inexpensive and easy to get. Also, it lets us test many of the body’s metabolic functions. For example, we know that both a low and high pH can cause different types of kidney stones.

Finally, with the rest of the urinary parameters, pH is an important element when doing different tests and follow-ups.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.