Comparative analysis of dideoxy sequencing, the KRAS StripAssay and pyrosequencing for detection of KRAS mutation

Table 1 Sensitivity of the 3 methods in mutation detection

Methods	Mutant DNA/total DNA (%)
	100	50	20	15	10	5	1	0
Dideoxy sequencing	Yes	Yes	Yes	Yes	No	No	No	No
Pyrosequencing	Yes	Yes	Yes	Yes	Yes	Yes	No	No
KRAS StripAssay	Yes	Yes	Yes	Yes	Yes	Yes	Yes	No

Dideoxy sequencing could identify mutations in dilutions containing ≥ 15% mutant DNA, pyrosequencing could identify mutation in dilutions containing ≥ 5% mutant DNA, the KRAS StripAssay could identify mutant DNA as low as 1%.

Table 2 Discrepant results detected by the 3 methods

Sample No.	Mutation type
	Dideoxy sequencing	KRAS StripAssay	Pyrosequencing
5	Wild-type	Wild-type	GGT>GAT
11	Wild-type	GGT>TGT	Wild-type
14	Wild-type	GGT>GTT	Wild-type
29	GGT>GTT	GGT>GTT	Wild-type
44	Wild-type	Wild-type	GGT>GAT
46	Wild-type	Wild-type	GGT>GAT
48	Wild-type	Wild-type	GGT>GAT
71	Wild-type	GGT>GCT	Wild-type

These results were repeated at least twice.