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Departments & Programs,UW Hospital and Clinics,Pulmonary Diagnostic Lab

Testing Terms

Testing Terms - Departments & Programs, UW Hospital and Clinics, Pulmonary Diagnostic Lab


FVC (Forced Vital Capacity): The maximum amount of air that can be forcefully exhaled from a maximal inspiration.

FEV1 (Forced Expiratory Volume 1 sec): The volume of air forcefully expired in the first second of a forced vital capacity maneuver.

FEV1/FVC%: The FEV1 compared to the FVC. This is expressed as a percentage.

PEF (Peak Expiratory Flow): Maximal flow rate achieved during a forced maneuver. This can be expressed in liters per second or liters per minute. Small portable Peak Flow Meters are used for following asthmatics.

FEF 25-75% (Forced Expiratory Flow 25-75%): Average flow rate during the middle half of a forced expiratory maneuver. This measures flow rates within the small airways.

DLCO (Diffusing Capacity): Gas distribution can be measured in a number of different ways. UW Health Pulmonary Function Lab measures diffusing capacity, DLCO, by a single breath method. The DLCOsb test measures factors that affect diffusion of gas across the alveolar-capillary membrane. The gas mixture that the subject inspires includes a small amount of carbon monoxide. It is the transfer of CO that is actually measured.

MVV (Maximum Voluntary Ventilation): The largest volume of air breathed over a 12-second period.

RAW Airway Resistance: Difference in pressure between the mouth and the alveoli, related to gas flow at the mouth.

IOS (Impulse Oscillimetry): This is a newer method in measuring resistance of the airways. IOS is based on the measurement of the relationship between an external pressure pulse applied to the respiratory system and the resulting respiratory flow. (H.Bisgaard, B.Klug, 1995)

RMF (Respiratory Muscle Forces): Both the inspiratory and expiratory muscle strength can be measured independently of each other.

SpO2: Pulse Oximetry

ABG: Arterial Blood Gas