Venous Blood pH Calculator

Created by Małgorzata Koperska, MD
Last updated: Mar 03, 2021

The venous blood gas calculator estimates the venous blood pH, using the values of bicarbonate (HCO₃) and arterial carbon dioxide partial pressure (PaCO₂) in the patient's blood. To do so, we apply the Henderson-Hasselbalch equation developed in 1908 by Dr. Lawrence Joseph Henderson and then improved by Dr. Karl Albert Hasselbalch.

If you'd like to estimate arterial blood pH and learn more about it, use our arterial blood pH calculator.

What can you calculate using venous blood gas levels?

Some of the most important information that can be gained from the blood gas values is blood pH. pH is a measure of acidity or alkalinity of any solution. Normal pH value ranges for venous blood are 7.31-7.41, while normal pH of arterial blood is 7.35 - 7.45. It means that venous blood is more acidic than arterial. It's due to the fact that there is more of the acidic carbon dioxide (CO₂) in the venous blood.

If the calculated pH is lower than the norm, it indicates acidosis, and if it's higher - informs us about alkalosis. These states of acid-base imbalance can be symptoms of respiratory or metabolic disorders. The body's acid-base homeostasis is a very complicated system - if it's an interesting topic for you, you can read more about it e.g. in the .

Calculating venous blood gas with the Henderson-Hasselbalch equation

The formula developed by Dr. Henderson described the use of carbonic acid as a buffer solution. Then, Dr. Hasselbalch re-expressed that formula in a more complicated manner to study acid-base disorders, which resulted in the Henderson–Hasselbalch equation. It describes the pH as a measure of acidity in biological and chemical systems.

For medical use, it calculates the pH of the blood by inserting the HCO₃ (in mEq/L or mmol/L) and PaCO₂ (in mmHg or torr) values in the following formula:

pH = 6.1 + log10 ( HCO₃ / ( 0.0308 * PaCO₂ ) )

Małgorzata Koperska, MD
Bicarbonate (HCO₃)
mEq/L
Carbon dioxide partial pressure (PaCO₂)
mmHg
Venous blood pH
People also viewed…

Christmas tree

Welcome to the Christmas tree calculator, where you will find how to decorate your Christmas tree in the best way. Take a look at the perfect Christmas tree formula prepared by math professors and improved by physicists. Plan in advance how many lights and decorations you'll need!

Pregnancy test

With the pregnancy test calculator, you can check when the best time is to take your pregnancy test!

QUICKI

QUICKI calculator measures insulin sensitivity based on fasting insulin and glucose levels obtained from the blood sample.

Schwarzschild radius

Calculate the gravitational acceleration at the event horizon of a black hole of a given mass using the Schwarzschild radius calculator.
main background