Quality control in the pulmonary function laboratory.

The addition of computers to pulmonary function laboratories has reduced quality-control problems. After standards for a test have been selected, the computer can enforce adherence to them. The computer can be programmed to perform periodic calibration checks and other self-diagnostic procedures to ensure that instrumentation and human errors have not gone undetected. The computer can be used to verify that reference values are within acceptable limits and that results for a particular patient are at least internally consistent. The computer greatly reduces the number of measurements and calculations that must be done by hand and therefore improves laboratory efficiency and reduces the probability of human error. Quality-control samples can be processed more frequently with the use of a computer because this task consumes less time than when done by laboratory personnel. Some disadvantages of quality control that have appeared since the introduction of the computer are the potential for undetected failure of computer hardware and software, a risk that has increased with the increase in software complexity, and the potential for the loss of large amounts of information because of its being stored on a single digital medium. To effect quality control in the pulmonary function laboratory one should (1) ensure that procedures and software conform to standards, (2) follow routine calibration-check procedures, (3) check test results for internal consistency and for consistency with other test results, (4) conduct periodic testing of a quality-control subject or reference sample, (5) continually evaluate software performance, (6) carefully evaluate changes in instrumentation and software, and (7) maintain duplicate copies of data on different types of mass storage media.