IFCC recommendation: The theory of reference values. Part 4. Control of analytical variation in the production, transfer and application of reference values

This paper is the fourth in a series of Recommendations on the Theory of Reference Values. The others cover:Part 1. The Concept of Reference Values [1].Part 2. Selection of Individuals for the Production of Reference Values [2].Part 3. Preparation of Individuals and Collection of Specimens for the Production of Reference Values [3].Part 5. Statistical Treatment of Collected Reference Values. Determination of Reference Limits [4].Part 6. Presentation of Observed Values Related to Reference Values [5].A Guide to the Documents is currently in preparation.The Expert Panel of Theory of Reference Values (EPTRV) was created in 1970 by the Committee on Standards (at present: Scientific Division) of the International Federation of Clinical Chemistry (IFCC). Its task was to develop a nomenclature and recommend procedures for the production of reference values and their treatment, and presentation of observed values in relation to reference data.The first document in the above-mentioned series describes the subject of reference values and defines various terms. It would be best to read it for a thorough understanding of the present document.