The use of three baseline values in intervention studies: application to evaluation of immune modulation therapies.

In studying the effects of a treatment intervention on immunological parameters, we have found that three baseline values are a practical number to obtain on each patient. Three baseline values 1) increase the chances of detecting a statistically significant effect of the intervention, 2) provide an assessment of the daily variability of the assay and patients, and 3) enable the identification of individual patients who demonstrate significant changes associated with the intervention.