The present invention relates to a method for a measurement system configured to test a flexible bio-process bag, the method comprising providing at least one flexible bio-process bag having a volume, wherein the at least one flexible bio-process bag is initially filled with a gas and inflated to a reference pressure (Pu), obtaining a leak model, obtaining baseline information, wherein the baseline information comprises at least a weighed first mass value (mbaseline) and a first time value (t1), obtaining evaluation information, wherein the evaluation information comprises at least a weighed second mass value (mevaluation) and a second time value (t2), testing the flexible bio-process bag based on the leak model, the baseline information and the evaluation information.