A device is provided for in vivo determination of at least one blood value within an object to be examined. The device includes a catheter-shaped carrier that may be inserted into the object to be examined. The catheter-shaped carrier has at least one measuring device, of which the measurement position is arranged at a definable position of the catheter-shaped carrier, and which is designed to repeatedly determine at least one blood value and to supply this value to an evaluation unit. Moreover, a corresponding method is described for in vivo determination of at least one blood value within an object to be examined.
