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Blood gas pH

Blood gases · also printed as pH (blood gas), Arterial pH, ABG pH, VBG pH, pH (arterial)

Typical UK adult range7.35 to 7.45 pH

Ranges vary between laboratories; the range printed on the report takes precedence.

What this test measures

The pH of the blood measures how acidic or alkaline it is. The body keeps it within a very narrow band by adjusting breathing and kidney function.

Why doctors request it

Measured on a blood gas sample in hospital, usually from an artery, when someone is acutely unwell or has breathing difficulty.

What commonly pushes it up

Over-breathing
Vomiting or loss of stomach acid
Some water tablets as a class

What commonly pushes it down

Under-breathing or lung disease
Kidney failure
Diabetic ketoacidosis
Severe infection or poor circulation
Some poisonings

Everyday reasons for a value outside the range

Venous samples read slightly lower than arterial
Air bubbles or delay change the result

About the sample

Taken and analysed within minutes.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

Got a report with Blood gas pH on it?

Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.