sealing and or closing caps of the catheters 24 and 22 not shown in the figure the feed tube 23 is preferably of a standard length of 150 or 180 mm whilst the aspiration tube 21 presumably has an approximate minimum length of 30 mm preferably 60 to 120 mm possibly even 180 mm this arrangement therefore clearly shows that this port body may be used both for the supply of drugs through the feed catheter 24 and for access to body fluids through the aspiration catheter 22 the tubes 23 and 21 preferably extend into the patient 39 s abdominal cavity where cell fluid can be found which may be provided with a drug or analysed for specific concentrations the dashed arrows show selected various test sites for testing the concentration or existence of certain substances for example a sensor may be applied to test point 25 where fluid is aspired from the bottom end of the catheter 22 somewhat upwards in order to perform a test precisely at this intermediate point 25 as described above a sensor attached at point 25 would be protected against deposits by the lower section of the tube 21 and or the catheter 22 when a test is performed at a point where no major deposits are to be expected a test sensor may also be attached permanently or removably at a point marked by the dashed arrow 26 the benefit of this detection method lies.