Quality control of vital capacity as a primary outcome measure during phase III therapeutic clinical trial in amyotrophic lateral sclerosis.

Currently, ALS clinical trials require large sample size and the participation of many clinical evaluators to perform the outcome measure. High variability due to testers, instruments, or patients performance errors may result in systematic bias or random error leading to erroneous or uninterpretable results. Consequently, a quality control system that aims to produce high quality data in terms of reproducibility and accuracy to ensure reliability of the primary outcome measure is essential.