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Emergency Blood Gas pH, Unspecified Source

Published: August 9, 2026Updated: August 16, 2026

Measures the pH of a blood sample to assess blood acidity, usually as part of an emergency blood gas evaluation.

Quick summary

["An abnormal blood pH may signal a serious acid-base imbalance that requires prompt clinical assessment."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
92198-1
Short code
PH emerg budget source
Synonyms
PH emerg budget source
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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?

This test measures blood pH, which shows how acidic or alkaline the blood is. It is commonly obtained as part of an emergency blood gas panel, which may also measure oxygen and carbon dioxide.

Why might I need this test?

Emergency clinicians may order it when there is severe shortness of breath, confusion, weakness, shock, poisoning, heart or lung problems, or a sudden change in a person's condition. The results can help assess oxygenation, carbon dioxide removal, and the body's acid-base balance.

How is the test performed?

A small blood sample is usually collected from an artery, a vein, or a capillary depending on the clinical situation and available equipment. The sample is analyzed promptly by a blood gas instrument, and results are reported with the other components of the blood gas panel.

How do I prepare for the test?

No special preparation or fasting is usually required. Because this test is often performed in urgent circumstances, follow your clinician's instructions and tell the care team about recent oxygen use, medical conditions, medications, or possible poisoning.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A lower-than-expected blood pH may indicate acidemia, while a higher-than-expected pH may indicate alkalosis. Possible causes include breathing problems, kidney or liver dysfunction, severe dehydration, shock, medication effects, or toxic exposure. Because pH must be interpreted with the rest of the blood gas results and the person's symptoms, an abnormal result should be reviewed promptly by a clinician.

Short name

Emergency blood gas pH

Frequently asked questions

Does a blood gas pH test measure the same thing as a standard blood test?
Not exactly. A blood gas test analyzes a freshly collected blood sample for pH and, often, oxygen and carbon dioxide. Results may be available very quickly, which is especially useful in emergencies.
Does the blood sample have to come from an artery?
No. Depending on the situation, blood may be taken from an artery, vein, or capillary. The test slug does not identify the source, and the source can affect how the pH and other results are interpreted.
What should I do if my blood gas pH is abnormal?
Contact the ordering clinician promptly, especially if the test was done for symptoms such as trouble breathing, confusion, fainting, or severe weakness. Treatment depends on the cause and the complete blood gas results rather than the pH alone.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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