Long COVID Atlas › Glossary › Impaired gas transfer
MechanismImpaired gas transfer
https://longcovidatlas.org/glossary/impaired-gas-transfer
In plain language
What it is
Oxygen crossing from the air sacs into the blood less easily than it should, sometimes even when a CT scan and breathing test look normal.
Why it matters
It gives a physical reason for breathlessness that ordinary lung tests keep calling normal.
Think of it like
A doorway that looks fine in a photo but quietly lets fewer people through than it used to.
For specialists
Formal definition
Reduced transfer of gas across the alveolar-capillary membrane, measured as a fall in diffusing capacity (TLco/DLCO) or, regionally, on hyperpolarized xenon MRI.
Mechanism
The defect can sit in the membrane, the small pulmonary vessels, or the red cells receiving the oxygen; xenon MRI separates the red-cell compartment from tissue and plasma.
Sources
- Impaired RBC-to-tissue-plasma gas transfer and reduced TLco on xenon MRI in long COVID (preprint) preprint ›