BTPS Correction Calculator
The BTPS (Body Temperature and Pressure Saturated) correction factor allows one to convert spirometer volume measurements to reflect the actual volumes in the lung.
A BTPS gas volume has been expressed as if it were saturated with water vapor (partial pressure of 47 mmHg or 6.2 kPa), at body temperature (37°C) and at the ambient barometric pressure; used for measurements of lung volumes.
The STPD (Standard Temperature and Pressure Dry) gas volume is expressed at 0 degrees C, standard pressure (760 mmHg), and assumes that the air is dry with no water vapour.
Volume (BTPS) = Volume
STPD) · BTPS correction factor