A method of controlling data information between a plurality of portable apparatuses for use by a patient for medical self-treatment, the treatment including a first operation and at least a second operation, said plurality of apparatuses comprising a first apparatus for performing the first operation, and at least a second apparatus for performing the second operation, each of said first and second apparatuses comprising a means for storing, processing and/or displaying information for transmitting and receiving of information and a means so that each apparatus is able to exchange date with said other apparatus, wherein the method comprises the steps of:
- (a) dynamically designating a single apparatus as a functional maser module among said at least two apparatuses;
- (b) initiating an attempted data communication between said apparatuses on request, said communication being controlled by said functional master module;
- (c) receiving and storing in said functional master module relevant information generated in said other apparatus;
- and wherein the apparatuses are selected from the group of:
- at least one lancet device;
- at least one body fluid analyzer;
- at least one drug administration system for administering a predetermined dose of medication to the patient;
- and
- at least one sensor for obtaining body characteristics.