The platelet survival module calculates the half-life and the percentage of platelets destroyed per day, the mean platelet life span, and the recovery (at t = 0). The calculations use a linear model, an exponential model and the weighted average of both models, as well as the regression coefficients of both the linear function and the exponential function. The screens of this module include calculations for a minimum of 6 specimens and a maximum of 12 specimens. The user has to enter the activity of the dose syringe before and after injection, the activity of the standard syringe before and after the contents are poured into the dilution flask, the volume of the dilution flask, the radioactive concentration of the dilute standard, the venous hematocrit, the radioactive concentration and times of withdrawal of the blood and plasma specimens, and the background radioactivity if necessary.