Table 3

Comparability of KRAS Mutational Analysis Using the κ Statistic

κ (95% CI) [n]*

Allele-Specific PCR (HistoGeneX/DxS)

Direct Sequencing (Gentris)

Allele-Specific Hybridization (Invitek)

Allele-Specific PCR Extensions (Genzyme)

Picotiter Plate Sequencing (Agencourt)


Direct sequencing (Amgen)

0.95 (0.85, 1.00) [40]

0.75 (0.52, 0.98) [32]

0.13 (–0.15, 0.42) [27]

0.94 (0.83, 1.00) [35]

0.94 (0.82, 1.00) [32]

Allele-specific PCR (HistoGeneX/DxS)

0.75 (0.52, 0.98) [32]

0.11 (–0.16, 0.37) [27]

0.89 (0.73, 1.00) [35]

0.88 (0.71, 1.00) [32]

Direct sequencing (Gentris)

0.75 (0.52, 0.98) [32]

–0.09 (–0.27, 0.08) [21]

0.74 (0.51, 0.98) [31]

0.63 (0.35, 0.92) [27]

Allele-specific hybridization (Invitek)

0.11 (–0.16, 0.37) [27]

–0.09(–0.27, 0.08) [21]

–0.08(–0.22, 0.06) [25]

0.29 (–0.05, 0.63) [21]

Allele-specific PCR extensions (Genzyme)

0.89 (0.73, 1.00) [35]

0.74 (0.51, 0.98) [31]

–0.08(–0.22, 0.06) [25]

1.00 (1.00, 1.00) [28]

Picotiter plate sequencing (Agencourt)

0.88 (0.71, 1.00) [32]

0.63 (0.35, 0.92) [27]

0.29 (–0.05, 0.63) [21]

1.00 (1.00, 1.00) [28]


PCR = polymerase chain reaction.

*The κ statistic [10] measures agreement for KRAS mutational status (wild type vs mutant), with a value of 1.0 indicating perfect agreement and a value of -1.0 indicating perfect disagreement. Values in brackets are the 95% CI for the κ statistic. Values in square brackets indicate the number of samples being compared by the κ statistic (ie, the number of samples for which the 2 assays being compared both had a determination of wild-type or mutant).

Oliner et al. Diagnostic Pathology 2010 5:23   doi:10.1186/1746-1596-5-23

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