extracorporeal signal the diagnostic apparatus is advantageously additionally provided with an apparatus for storing the measurement signals which can then be called up as required a preferred embodiment of the measurement chamber is illustrated in fig2 a plurality of said measurement chambers are advantageously combined to form a diagnostic apparatus the number of individual measurement chambers preferably being from 20 to 50 the number as such is non critical if one determination per week is assumed then a number of 50 u00b1 10 appears to be particularly advantageous since one exchange per year is sufficient in this case the inventive method and device can be furished both for flow rate measurements and for individual determinations the possibility of contactless signal transmission means that it can advantageously be used both for in and outpatients without additionally restricting the patients 39 mobility the signal transmission methods are known per se to a person skilled in the art the structure of one embodiment of the device is illustrated in fig1 the structure of a specific measurement chamber is illustrated in fig2 a the production of sufficiently small measurement chambers is possible by the methods which are known per se to a person skilled in the art the closure of the measurement chambers is especially important magnetically actuable closure flaps which can assume two fixed states flip flops can advantageously be used.