Interlaboratorium

Interlaboratorium, or interlaboratory, refers to activities in which multiple laboratories perform analyses on the same samples to assess and improve the comparability and reliability of measurements. The term is used in English as interlaboratory or inter-laboratory, and is often framed as interlaboratory comparison or proficiency testing.

In typical interlaboratory studies, a central provider prepares a set of homogeneous samples with known properties and distributes them to participating laboratories. Labs analyze the samples using their routine methods, report results, and the organizing body compiles a data set. Statistical evaluation produces indicators of performance such as mean or consensus values, standard deviation, coefficients of variation, and z-scores or En scores that indicate bias and precision relative to reference values.

Interlaboratory activities are used to validate methods, establish traceability to reference standards, verify instrument performance, and support quality management in sectors like clinical chemistry, environmental analysis, food testing, and pharmaceutical analytics. They are formalized in standards and programs known as proficiency testing or interlaboratory comparison, with guidelines in ISO 17025, ISO 5725, and ISO 13528.

Advantages include the detection of systematic biases, calibration errors, and method limitations, enabling laboratories to benchmark against peers and demonstrate competence. Limitations include difficulties ensuring sample commutability, matrix effects, small participant counts, and costs and logistics of distributing samples. Overall, interlaboratory activities contribute to measurement quality and regulatory compliance.