diffusion capacity test

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Definition - What does diffusion capacity test mean?

Diffusion capacity testing is a clinical procedure that assesses the rate at which oxygen and carbon dioxide diffuses, or passes, across a thin membrane acting as a filter where alveoli (tiny air sacs) and blood capillaries lining lung tissue regulate the breathing process. Doctors employ diffusion capacity testing as an adjunct modality in evaluating the gaseous interchange between oxygen and carbon dioxide during regular breathing cycles to determine if individuals are candidates for cardiorespiratory conditions.

SureHire explains diffusion capacity test

Diffusing capacity of the lungs for carbon monoxide (DLCO) is a test where clinicians administer a slight trace of carbon monoxide through a mouthpiece that enters the lungs, serving as a benchmark to gauge the actual amount of the gas that diffuses into the bloodstream against a normative test value. A low diffusion capacity across the alveolar-capillary membrane carries epidemiological implications where scarification (thickening) or a reduced surface area can hinder respiration. Physicians may incorporate numerous tests in the diagnosis of an obstructive lung disease or restrictive lung disease affecting the quality of life.

In conducting a DLCO examination, the amount of carbon monoxide that diffuses through the lungs represents a percentage for concluding if lung function deviations exist, indicating a potential cardiorespiratory disease. Biological and physiological variables including age, gender, ethnicity, relative hemoglobin in the blood, and height can contribute to the metabolic performance of lung tissue where a DLCO measurement that falls below the 30% threshold constitutes a disability. Diffusion capacity testing is a viable method for ascertaining if gas exchange anomalies are the result of cardiopulmonary conditions including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, emphysema, pulmonary embolism (PE), and lung tissue lesions (scarring) that can make breathing difficult.

Although the primary role of the lungs is respiration, it also helps support other homeostatic functions and processes including maintaining ph balance levels, body temperature, and release of hormones to promote optimal health. In the workplace, airborne contaminants are environmental hazards that can compromise the structural integrity of lung tissue over time, impeding breathing patterns to the extent that job performance declines. However, in filing disability claims, extensive medical evidence that covers X-rays, diffusion capacity tests, and spirometry tests are a requirement to support symptoms that coincide with a particular respiratory condition.

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