ATS Pulmonary Function Laboratory Manual

ATS Pulmonary Function Laboratory Management & Procedure Manual | 3rd Edition

5.3. Figure 5.2 is an example of a control chart using a fixed UL and a fixed LL data from daily spirom- eter calibration using a 3.00-L syringe on one spirometer. 5.4. Control charts are helpful at detecting random and systematic errors. 5.5. The pattern of the data points on a control chart over time also allows the detection of trends. 5.5.1. One type of trend is the continuous movement of values in one direction over six or more consecutive values. 5.6. Control charts should: 5.6.1. Be constructed neatly 5.6.2. Large enough to plot values easily and to present a clear picture 5.6.3. Contain labels for both axes 5.6.4. Have the name of the test, instrument, or method; month and year; and the mean, UL, and LL printed on each chart. Calibration of Calibrators 1. Calibration devices (e.g., calibration syringes) should be checked regularly and records of checks retained in the quality control log (8, 9). 1.1. Leak testing (including any tubing) quarterly

Figure 5.2  An example of a control chart of calibration verification of a spirometer using a 3.00-L syringe. In this example, the UL and LL are fixed at ±3% of the volume of a 3.00-L calibration syringe (i.e., 3.09 L and 2.91 L). The control chart is for a 1-month time window, but others can be used. In addition, this control chart is for one spirometer. If ±3.5% of the volume of a 3.00-L calibration syringe is used (as recommended by more current guidelines), the UL and LL would be 3.11 L and 2.89 L, respectively.

48