The European Court of Justice (ECJ) has ruled on a reference from a Greek court (Case C6/05) concerning whether a tender for medical devices, duly certified as meeting EC standards and appropriately labelled with the "CE" marking, can be rejected from a procurement procedure at the technical assessment stage. The ECJ found that the principle of equal treatment and the obligation of transparency preclude such unilateral action unless justified by the outcome of a special safeguard procedure. In order to comply, the relevant Member State may, having notified the European Commission, take interim measures to withdraw a certified medical device from the market. It is the Commission's role to decide whether or not the device complies with necessary standards. The contracting authority must wait for the outcome before proceeding with the procurement process.