Method for detecting abnormal spots of nucleic acid microarray

A nucleic acid analyzing method for examining an amount of a target nucleic acid having a target sequence (a) using a nucleic acid microarray, wherein

• the nucleic acid microarray has a plurality of spots to which a probe nucleic acid is immobilized, and
• in an optional spot (X1m) of the plurality of spots, a probe nucleic acid including a probe sequence (a′) complementary to the target sequence (a) and a sequence (b′) different from the probe sequence (a′) is immobilized, where m denotes a given integer,
• the method comprising:
• hybridizing the sequence (b′) with a sequence (b) by adding an labeled abnormality detecting nucleic acid (B) including the sequence (b), which can be bound to the sequence (b′), to the spot (X1m) on the nucleic acid microarray;
• obtaining a labeled amount value (Fc1m) of the hybridized abnormality detecting nucleic acid (B) in the spot (X1m);
• and
• determining, based on the measured labeled amount value (Fc1m), as to whether or not the spot (X1m) is an abnormal spot having an abnormal hybridization ability.