Do we have linearity data for all EliA analytes?
All EliA assays have very broad measuring ranges. In practice, patient samples will rarely exceed these ranges and, thus, a linearity in dilution is not often needed in practice.
For samples which do exceed the measuring range, the actual quantitation is rarely clinically significant. It is enough to state that the result is "greater than..."
In all studies on linearity in EliA the specifications were set very narrowly with O/E= 0.8-1.2. It was found in a separate study (see validation plan UEVPPC03-02) that "a linearity for all tests and all sera is not achievable inside the targets O/E= 0.8-1.2 due to the unique calibrator system in ImmunoCAP".
Statements on linearity are made under these restrictions.
Limitations on linearity are stated in the respective DfU: "Please note that due to differing binding characteristics of the antibodies in patient samples, not all sera can be diluted linearly within the measuring range."
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