pH Test
A pH test measures how acidic or alkaline a sample of your body fluid is by using a special chemical test strip, giving your doctor valuable information about your body's acid-base balance and overall health.
{"pH measures the acidity or alkalinity of body fluid on a scale of 0-14","Normal blood pH ranges from 7.35 to 7.45","Abnormal pH may indicate kidney problems, breathing issues, or metabolic disorders","The test uses a color-changing strip that is compared to a reference chart","Results help doctors diagnose and monitor certain medical conditions"}
Key facts at a glance
- LOINC
- 50896-0
- Short code
- pH Fld Strip
- Synonyms
- pH Fld Strip
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- not specified
- Ref low
- 7.35
- Ref high
- 7.45
- Critical range
- 7.2 not specified – —
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- test-strip
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
The pH test measures the hydrogen ion concentration in your body fluid, indicating how acidic or alkaline (basic) the fluid is. The test uses a chemical test strip that changes color when dipped into the fluid sample. This color is then compared to a standardized chart to determine the pH value.
How is the test performed?
A healthcare provider will collect a sample of your body fluid (such as urine or blood serum). For this test, the sample type is serum, which is the liquid part of blood after it has clotted. The test strip is dipped into the sample, and the color change indicates the pH level. The process is quick and usually takes only a few seconds.
Do I need to prepare for the test?
Your doctor may give you specific instructions. For blood pH tests, you may need to fast (not eat) for a certain period before the sample is taken. For urine pH tests, you may be asked to collect a first-morning sample. Always follow your healthcare provider's instructions and inform them about any medications or supplements you are taking.
What do the results mean?
The pH scale ranges from 0 to 14, with 7 being neutral. Below 7 is acidic, and above 7 is alkaline (basic). For blood (serum), the normal range is tightly controlled between 7.35 and 7.45. Values below 7.35 indicate acidosis, while values above 7.45 indicate alkalosis. Your doctor will interpret your results based on your overall health and other test findings.
Reference range
Varies by fluid type (typically ~7.35-7.45)not specified
None required; collect in sterile container without delay
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
FLpH
Frequently asked questions
Is the pH test painful?
How long does it take to get results?
What can cause abnormal blood pH?
Can I test my pH at home?
Do I need to fast before this test?
Sources
- 1
- 2Mayo Clinic - AcidosisSource
- 3Lab Tests Online - pHSource
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