In In re Blood Reagents Antitrust Litigation, 783 F.3d 183 (3d Cir. 2015) (No. 12-4067), the district court certified a class in plaintiffs’ suit alleging defendants violated the antitrust laws by conspiring to fix the prices of blood reagent products. On appeal pursuant to Rule 23(f), the Third Circuit held plaintiffs must show on class certification, based on all relevant evidence, that the requirements of Rule 23 have been satisfied, not simply provide an assurance that the requirements will be met. In making that factual determination, the district court may rely on expert proof. Where it does so, the expert testimony must satisfy the Daubert requirements.