Method and apparatus for analyzing a sample

The invention relates to an apparatus and a method for analyzing a compound to be drawn from a patient's organ. The apparatus comprises a sampling element having a wall which a compound to be analyzed is capable of penetrating. The apparatus also includes a pressure-difference producing element which, through the action of a pressure-difference, is capable of delivering a sample along a tube extending from the sampling element. The apparatus also includes an analyzer capable of performing an analysis on a sample drawn from the sampling element. The analyzer is in flow communication with the sampling element by way of the tube. According to the method, a mixture consisting of a medium and a compound drawn from the organ is delivered to the analyzer for a subsequent analysis, and at least some of the mixture is returned from the analyzer back to the sampling element.