Blood will be drawn four times. The samples will be analyzed as soon as possible after each procedure day. Some analyses will be at the Sahlgrenska Academy directly, others will be delivered to Sahlgrenska University central lab (please see section 6.1 for details). These analyses are routine but samples may be stored for a few days before the measurement takes place. This depends on when the central lab can accept our samples and on their specific working load. Sample storage and handling will be performed according to the central labs recommendations.