Linearity was determined using mixtures of plasmids carrying the wild-type or mutant sequence for the mutations GGC->AGC codon 719, ACG->ATG in codon 790, CTG->CGG in codon 858, and the deletions 2235del15 and 2236del15 in Exon 19 (see figure " Linearity of deletion 2235del15"). The plasmids were mixed in proportions to give four levels of mutation (5, 10, 30, and 50%). Each mixture was analyzed with three different lots of the therascreen EGFR Pyro Kit in three Pyrosequencing runs with three replicates each.
The results were linear within an allowable nonlinearity of 5 % units in the tested range of 5 to 50% mutation level. Similar results were obtained for the mutations GGC->AGC in codon 719, ACG->ATG in codon 790, CTG->CGG in codon 858, and the deletion 2236del15 in Exon 19.
The precision data allows the determination of the total variability of the assays and was obtained at three different levels by analysis of the above mentioned plasmid mixtures with three replicates each.
Repeatability (intra-assay and inter-batch variability) was calculated based on the data for determination of linearity (three runs on the same day using varying lots of the therascreen EGFR Pyro Kit). Intermediate precision (intra laboratory variability) was determined in three runs within one laboratory on three different days with varying operators, PyroMark Q24 instruments, and lots of the therascreen EGFR Pyro Kit. Reproducibility (inter-laboratory variability) was calculated from two runs each in an internal and external laboratory and using varying lots of the therascreen EGFR Pyro Kit.
Precision estimates are expressed as standard deviation of the measured mutation frequencies in % units. The repeatability, intermediate precision, and reproducibility for the deletion 2235del15 in exon 19 was 0.8–1.2, 0.7–2.9, and 0.7–1.8 % units, respectively, in the measured range of 5 to 50% mutation level. Similar results were obtained for the mutations GGC->AGC in codon 719, ACG->ATG in codon 790, CTG->CGG in codon 858, and the deletion 2236del15 in exon 19.
Precision for the deletion 2235del15 in Exon 19
|% mutated plasmid ||Repeatability (Mean, SD) ||Intermediate precision (Mean, SD) ||Reproducibility (Mean, SD)|
|5 ||7.7, 0.8 ||7.4, 0.7||7.4, 0.7|
|10 ||14.7, 1.1 ||14.5, 1.3||14.4, 1.1|
|30 ||41.8, 1.2 ||40.0, 2.0||41.5, 1.7|
|50 ||59.4, 1.0 ||58.2, 2.9||60.7, 1.8|