Objective: Review on the current state of reference intervals. Problems of their establishment, application and validation namely in connection to IVD Directive 98/79 EC. Method: Review of the recommendations, conceptions, and results of important multicentric regional studies. Procedures of reference interval validation. Results and Conclusions: Data on the reference intervals obtained from manufacturers of IVD are main tool for interpretation of laboratory results. Reference intervals must be validated by laboratories. Reaching the traceability and comparability of analytical results is necessary for validity of reference values. Establishment of own laboratory reference intervals is totally inappropriate not only from financial but also from scientific reasons. Shared responsibility of manufacturers (according to Directive 98/79 EC) and medical laboratories (according to ISO 15189), strong application of metrology, multicentric studies for establishment or validation are basis for modern concept in reference limits. Activities in field of reference limits should be realised on the basis co-operation between manufacturers and laboratory scientists and should be managed and organised form national even international centres.

        Key words: reference interval, decision limit, validation, IVD, traceability.