Respiratory

pH

Normal Range
7.35 - 7.45
Sample Type
Standard
Fasting
No
Unit
pH units

Arterial pH is a measure of the hydrogen ion concentration in the blood, indicating the acid-base status of the body. Within the context of an Arterial Blood Gas (ABG) panel, it is the primary indicator of acidemia or alkalemia. Maintaining pH within a narrow range (7.35–7.45) is critical for protein structure, enzyme function, and overall cellular metabolism. The pH value, when combined with $pCO_2$ and $HCO_3^-$ levels, allows clinicians to distinguish between respiratory and metabolic acid-base disturbances.

Check Your Result

Check Your Result

Interactive
pH units

Enter your lab result to see where you stand compared to the standard reference range.

Why Context Matters

pH measurements can be falsely altered by technical factors such as air bubbles in the syringe (which increases pH), excessive heparin (which decreases pH), or delays in sample analysis (leukocyte metabolism decreases pH). Additionally, a 'normal' pH can coexist with severe mixed acid-base disorders where a metabolic acidosis and respiratory alkalosis cancel each other out.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for pH:

Research & Guidelines

Related Indicators

DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

Get Notified When Dr. Babu Is Available