The Science Journal of the American Association for Respiratory Care
For decades pulmonary function (PF) testing has been performed to measure various lung volumes and capacities. These PF data results are used by physicians in all aspects of care for patients with pulmonary problems. Because of the integral role of pulmonary function test in patient care, it is imperative that these measurements be an accurate reflection of the patient's lung functions. There is continuous advancements in PF testing technology, but more important, employees often must seek alternative health care providers when employers change health care plans or they change employment. Therefore, there is a need to validate the accuracy of PF data produced between PF testing laboratories within a city or region. Various organizations have published guidelines to standardize all aspects of pulmonary function testing. However, there are only a few publications documenting comparability of data between pulmonary function laboratories using normal subjects as ?biological controls.? This study evaluated the degree of variability of pulmonary function test measurements between three PF laboratories in a large metropolitan city. It was not the intent of this study to identify the cause of any significant variability but only if differences existed. Eight healthy, non-smoking study subjects performed complete pulmonary function studies at three PF laboratories in our city. Instructions were administered by the same personnel at each PF laboratory to study subjects on three consecutive days at the same time of day. A rotation schedule was developed so that there was equal first, second and third visits to each laboratory. Descriptive statistics were calculated for each of the study subjects on each of the pulmonary function tests measured. A repeated measure univariate analysis was performed on the data. Listed below are averages of individual test differences of the high and low measurements between the laboratories.
|SVC||= 0.46 L.*||PEF||= 2.00 L/sec*.|
|FRC||= 0.59 L.*||FEF 25%-75%||= 0.85 L.|
|RV||= 0.53 L.||DLCO||= 4.38 mL/min/mmHg*|
|TLC||= 0.71 L.*||AV/DLCO||= 0.78|
|FVC||= 0.47 L.*||DL/AV||= 0.68|
|FEV1.0s||= 0.41 L.*|
Group measurements indicated with an * show significant variability among the three study sites. All individual averages show significant variability. The results from this study indicate PF testing laboratories should consider reviewing their calibration procedures and quality control protocols and initiating the use of "biological controls" as a part to diagnostic laboratory quality assurance.