Understanding Your Medical Test: Purpose, Preparation, Sample Collection, and Results
A test that measures the acidity or alkalinity level in your urine collected over 24 hours to help evaluate kidney function and detect certain medical conditions.
{"Measures urine acidity/alkalinity over a 24-hour period","Helps diagnose kidney stones, urinary tract infections, and metabolic disorders","Results are influenced by diet, medications, and underlying health conditions","Collect all urine in a special container for 24 hours","Normal urine pH typically ranges from 4.5 to 8.0"}
Key facts at a glance
- LOINC
- 27378-9
- Short code
- UrinepH24
- Synonyms
- pH 24h Ur
- Category
- chemistry
- Sample
- serum
- Container
- 24-hour urine collection container (plastic or glass with graduated markings), may include preservative depending on laboratory protocol
- Units
- not specified
- Ref low
- 4.5
- Ref high
- 8
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Potentiometry using glass pH electrode or ion-selective electrode (ISE)
- CPT
- 81001
- SNOMED
- 27144000
- Specimen volume
- Complete 24-hour collection, typically 1000-2000 mL total volume
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 48-72 hours; Frozen (-20°C): several weeks for pH analysis
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test, and what does it measure or help your healthcare team evaluate?
The 24-hour urine pH test measures the hydrogen ion concentration in your urine, indicating how acidic or alkaline (basic) your urine is. Unlike a single urine sample, collecting urine over 24 hours provides a more accurate picture of your urinary acid-base balance, as pH levels can vary throughout the day based on diet, activity, and other factors.
Why is this test performed, and how might the results help guide your diagnosis, treatment, or follow-up care?
Your healthcare provider may order this test to: evaluate kidney function and acid-base balance in the body; help diagnose and manage kidney stones (certain types of stones form in acidic vs. alkaline urine); detect urinary tract infections (bacteria that cause UTIs can change urine pH); monitor metabolic disorders such as renal tubular acidosis; assess the effectiveness of certain medications that affect urine pH; and evaluate dietary patterns that may impact urinary health.
How should you prepare for this test, and what steps are needed to collect and submit your sample correctly?
Before the test, inform your doctor about all medications, vitamins, and supplements you are taking, as some can affect urine pH. Avoid strenuous exercise during the collection period. On the day of collection, start by urinating into the toilet upon waking up. For the next 24 hours, collect all urine in the provided container, including the first morning urine of the second day. Keep the container refrigerated or in a cool place. Record the start and end times of collection. Return the container to the lab as instructed.
What do your results mean, and when should you discuss the findings, reference ranges, or next steps with your healthcare provider?
Normal urine pH typically ranges from 4.5 to 8.0, with an average around 6.0. Acidic urine (pH below 6.0) may indicate conditions such as diabetes, kidney stones, diarrhea, or a diet high in meat. Alkaline urine (pH above 7.0) may suggest urinary tract infections, kidney problems, or a vegetarian diet. Your doctor will interpret your results based on your overall health, symptoms, and other test findings.
Reference range
4.5-8.0not specified
Complete 24-hour urine collection; keep refrigerated during and after collection. No fasting required; diet and medications can influence pH.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Urine pH is a valuable diagnostic tool that reflects the body's acid-base balance and metabolic function. Acidic urine (pH < 6.0) is associated with increased risk of uric acid and cystine kidney stones, diabetic ketoacidosis, diarrhea, and high-protein diets. Alkaline urine (pH > 7.0) is linked to struvite kidney stones, urinary tract infections caused by urea-splitting bacteria, certain kidney disorders, and vegetarian diets. The 24-hour collection is particularly useful for monitoring patients with recurrent kidney stones, evaluating renal tubular function, and adjusting treatment for metabolic acidosis or alkalosis.
Frequently asked questions
Does the sample type say serum?
What can affect my urine pH results?
Is the 24-hour collection painful or uncomfortable?
What happens if I miss a urine sample during collection?
Will I need to fast before this test?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy