Analytical quality goals and assessment to ensure transferability of laboratory results

About 3 years ago NORDKEM started a project entitled 'Medical Need for Quality Specifications in Clinical Laboratories'. This communication describes the general approach of this project and a subproject oriented towards problems of transferability of clinical laboratory data. Attempts are made to estimate clinical goals for analytical measurements--either used alone or in combinations with other measurements or observations--in defined clinical situations. Various methodologies are used for the assessment of the clinical goals, starting, e.g., from clinical situations or biological reference data. The analytical quality specifications are expressed as total allowable errors. It is necessary to complement specifications of 'clinical goals' with data describing characteristics of the measurement procedure, preanalytical errors and internal and external quality assurance procedures in order to establish the laboratory quality specification guaranteed by the laboratory. Problems of transferability of clinical laboratory results occur both within a laboratory/hospital and between laboratories/hospitals/health care units, problems that sometimes make communication of laboratory results difficult or even meaningless. In order to study the transferability of clinical laboratory data within a health care region, so called 'transformation functions' could be used to characterize each laboratory in a strict quality assessment/proficiency testing procedure on the basis of analytical quality specifications. Under certain conditions, e.g. for analytical procedures with high specificity and documented stable analytical performance, numerical correction of analytical bias could be performed to decrease interlaboratory variation to a level specified by medical needs.