What Does Zero Flow Errors Mean?
Zero flow errors are a type of inaccuracy that may occur when a spirometry test is conducted using a flow-type spirometer. These errors occur when the baseline or zero reference point has been incorrectly calibrated prior to testing.
Because this error occurs during the calibration process, in effect establishing a new baseline for the test, it does not trigger an error registration as a malfunction or error during the test would. Spirometry technicians are trained to detect the presence of zero flow errors in the charted results of a patient's test.
WorkplaceTesting Explains Zero Flow Errors
Spirometry is a type of pulmonary function test (PFT). The spirometry test is also known as a lung function test. During a PFT using a spirometer, the test subject is asked to inhale and exhale through the device to assess his or her lung's volume capacity. The test also measures the individual's airflow capacity, or how quickly and forcefully her or she can exhale.
To confirm that the zero volume or baseline level of the spirometer is registered correctly, a known volume of air is introduced to the machine using a volume calibration syringe. This syringe serves as a control, allowing the technician to confirm that the device accurately measures this calibration volume.
If the measurement is off by more than approximately 3%, the device must be repaired. However, if the volume calibration syringe is improperly attached or defective, or the calibration is otherwise improperly performed, the baseline set by the calibration will be incorrect, thereby skewing the results of the subsequent lung function test