266. matching matrix Blank biological matrix or surrogate matrix prepared from a recipe, used for the preparation of calibration standard and quality control samples (QCs), intentionally similar to the matrix of (incurred) samples requiring analysis. Matrix matching is often used in analysis of biological fluids or tissue where blank tissue is unavailable or limited to best compensate for matrix effects. Given that the matrix can vary sample-to-sample and patient-to-patient in a clinical trial, it is not possible to unambiguously match the matrix in all respects.
267. matrix Whole blood, plasma, serum, urine or other biological matrix selected for analysis. A matrix not containing exogenous chemicals (except anticoagulant) and their metabolites is called blank matrix.
268. matrix effect The direct or indirect alteration in assay response (including sample preparation) due to the presence of matrix constituents in extracted samples.
