DLCO Diffusing Capacity Calculator

Measured DLCO Predicted DLCO DLCO Diffusing Capacity for Carbon Monoxide Explanation and Clinical Context DLCO describes the ability of the lungs to transfer carbon monoxide from the alveoli into the pulmonary capillary blood and is one of the most sensitive indicators of gas exchange function. A normal DLCO reflects adequate alveolar surface area, intact alveolar capillary membrane, and sufficient pulmonary blood volume for gas transfer. Values between eighty to one hundred twenty percent of predicted are considered normal.

A mild reduction typically ranges from sixty to eighty percent predicted while values below forty percent indicate severe impairment. Low DLCO can result from parenchymal lung disease pulmonary vascular disease pulmonary hypertension anemia or emphysema. Elevated DLCO may be seen in conditions with increased pulmonary blood volume such as left to right shunt asthma or polycythemia.

DLCO percent predicted guides interpretation together with spirometry and lung volume measurements and provides a structured approach to identifying restrictive obstructive or vascular patterns. A markedly reduced DLCO indicates impaired diffusion capacity which carries prognostic implications in interstitial lung disease pulmonary hypertension and advanced chronic obstructive pulmonary disease. Clinical assessment should integrate patient symptoms imaging and hemodynamic data to form a comprehensive decision.

Reference Macintyre N et al. Standardisation of the single breath determination of carbon monoxide uptake in the lung. European Respiratory Journal.

2005. Wanger J et al. Standardisation of the measurement of lung volumes.

European Respiratory Journal. 2005.