Urine pH is the measure of acidity or basicity of urine. If the pH of urine is 8 or higher, it is indicated to be a basic while if it is 6 or lower, it will be indicated as acidic. The pH level tells us about the health conditions of a body. 

Normal pH level and Range

The pH of urine is variable however, it may range from 4.5 8 (depending on the physiologic state), and it primarily depends upon the hydrogen ion concentration.

The kidney helps in the maintenance of pH by the excretion of hydrogen ions into the urine while reabsorbing the bicarbonate ions from the urine.

Urine pH - Normal range and Chart
Urine pH – Normal range and Chart

Abnormal pH level

 If the hydrogen ion concentration is greater, the range shown on the scale will be 4.5 or less. The greater the concentration of hydrogen ions, the more it would be acidic.

The pH level depends upon the hydrogen ion concentration in urine.

But if the hydrogen ion concentration is low, the range shown on the scale will be 9.5 or greater. The lower the concentration of hydrogen, the more it would be basic.

pH scale showing the optimum pH of different substances. images
Figure 1: pH scale showing the optimum pH of different substances.

Factor affecting pH

What a person eats daily plays a major role in affecting the acid-base balance. Food products having higher levels of hydrogen ions are considered to be acidic, and their consumption thus, makes the urine acidic.

 While the food products having lower concentrations of hydrogen ions are considered to be basic, and having those products, considerably, increases the urinary pH.

Examples of acidic food items

  • sodas
  • beans
  • high-sodium dressing
  • certain grains
  • some variety of cheese
  • Foods rich in protein

Examples of basic food items

  • Bread
  • Legumes
  • Vegetables
  • Rice
  • Fruit
  • Some dairy products
showing acidic and alkaline foods images pics
Figure 2: showing acidic and alkaline foods.

Significance

Urine pH is very significant as it informs one about the health issues one may face. Different medical conditions have different effects on urinary pH. Some conditions tends to decrease it while others causes it to increase.

Medical Conditions

If the urine pH is high, it will be an indication of alkalinity. Following conditions could be the probable signs of alkalinity.

  • Urinary tract infections (UTI)
  • Kidney Stone 
  • Renal disorders
  • Respiratory and metabolic alkalosis

The urine test can turn out to be alkaline if a person has had prolonged vomiting. By vomiting, a person gets rid of the stomach acid and thus it makes the body fluids more alkaline.

On the other hand, if the urine pH is low, it is a sign of acidity. Following conditions could be the probable signs of acidity.

  • Starvation
  • Diarrhea
  • Pyrexia
  • Respiratory and metabolic acidosis
Alkaline UrineAcidic Urine
Renal tubular acidosisDehydration 
Alkaline drugsAcidifying drugs
Diuretics (drugs usage)Fever
Urinary tract infectionsGout
VomitingDiabetes 
Metabolic and Respiratory AcidosisDiet high in protein
Pulmonary Emphysema 

Urine Analysis

Urine analysis is a set of ‘’qualitative’’ and ‘’semi-quantitative’’ analysis performed on urine samples. A routine urine analysis includes a physical examination, chemical analysis, and microscopic examination

Physical Examination

The routine checkup of the physical characteristics of urine includes its color, odor, pH, turbidity, and specific gravity.

A test is carried out to detect the pH of urine. A simple procedure for its detection starts by taking a fresh sample of urine in a beaker. Then a pH paper strip is dipped in it. After a while, it is checked for color change

Chemical Examination of Normal Constituents

The chemical examination includes the testing of its organic and inorganic constituents. 

  • Organic constituents that encompass the urine pH are Uric acid and Creatinine.
  • Different tests are undertaken for the detection of organic constituents.
  • The test used for uric acid detection is Ammoniacal Silver Nitrate, and the test for the detection of creatinine is the picric acid test or Jaffe’s test.
  • The inorganic constituents that affect the urine pH are Phosphates, Chlorides, and Calcium.
  • The examination of inorganic constituents can be done by undertaking some of the tests such as the Sulkowitch test. 

Microscopic Examination

The microscopic examination is a way to check and calculate the types of cast, crystals, cells,  and microorganisms that are present in the urine.

Method to detect the pH of urine:

The observation of the pH of urine is very important as it tells us about the patient’s health condition. To keep a record, frequent analysis of urine pH is important.

Dipstick Analysis

The urine dipstick test is a rapid test that analyses the urine. A dipstick Is a thin plastic strip that contains small squares of different colors. The square on the dipstick contains specific chemicals that react differently when they come in contact with urine. Each color measures one specific quality of urine.

Step 1: Dip strip briefly.

Dip stick analysis step 1 Dip strip briefly. image

Step 2: Withdraw the strip.

Dipstick analysis step 2 Withdraw the strip. images  picture

Step 3: Read the Results.

Dip stick analysis Read the Results image picture
How do you read urine dipstick results
How do you read or interpret urine pH dipstick results

Treatment

It is significant for a healthy life to have a good diet, a nutritious life never comes without a healthy diet. The first step towards a vigorous lifestyle is to consume normal and fibrous food. Devouring a balanced diet for several days can bring about a significant change in the urine pH. Consumption of Vegetables and fruit should be increased. 

The best treatment for the controlled urinary pH is to have a balanced diet. images picture
Figure 3: The best treatment for the controlled urinary pH is to have a balanced diet.

Frequently Asked Questions:

Q1. What are the symptoms of acidic urine?

Ans. Having increased amount of uric acid leads to kidney stones and that results in painful urine, blood in urine and foul smelling urine.

Q2. What is the drug therapy for alkaline urine pH?

Ans. The following therapies can be used for curing the alkalinity of urine; Sulfa therapy, kanamycin, salicylate intoxication, etc.

Q3: How is urine pH measured?

Ans. A reagent test strip is usually used for pH measurement. In the reagent strips most commonly, has two indicators, one methyl red and the other bromthymol blue and it gives different colors in different urine pH.

Q4. How does vitamin C affect urine pH?

Ans. Vitamin C limits the bacterial growth by acidifying the urine. So, vitamin C actually functions as an acidifier.

Q5. Which organ is mainly involved in regulation of acid-base balance?

Ans. The major organs involved in the regulation of acid-base balance in the body are the kidneys.

Q6. Does bacteria survive in alkaline pH?

Ans. In high pH bacteria does not survive. However, some bacteria may survive in low pH.

 References

  1. https://pubmed.ncbi.nlm.nih.gov/20407938/
  2. https://www.elsevier.com/books/T/A/9780702071676
  3. Textbook of Medical Biochemistry – U. Satyanarayana
  4. https://www.researchgate.net/profile/Malcolm-Brigden/publication/270904386_Urinalysis-Book_Chapter/links/54b98c4d0cf24e50e93dc7eb/Urinalysis-Book-Chapter.pdf
  5. https://www.sciencedirect.com/science/article/pii/B9781416066408000026

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