Table 5. Critical domains of gene expression for receptor status determination.

Receptor	Probeset	Xlower	Xupper
ER	205225_at	8.517	10.354
PGR	208305_at	3.664	4.407
HER2	216836_s_at	11.783	13.070

The critical domain for expression values x is given by $X_{\text{lower}}\le x\le X_{\text{upper}}$, based on the ExMax-algorithm and probe sets listed in Table 2. The section ‘Expression lookup plot’ in ‘Material and methods’ describes how to actually apply the criterion $X_{\text{lower}}\le x\le X_{\text{upper}}$