Table 9

Relative efficiency of the immunohistochemical (IHC) assay of the UK NEQAS organising laboratory in achieving optimal demonstration of oestrogen receptors in 152 breast carcinomas, fixed and processed in 152 different laboratories

Efficiency of IHC assaysn%χ2 Valuep Value
*IHC assay results awarded the same quick score as participant (±1 mark)
**IHC assay results awarded a quick score that was greater by 2 marks or more than that awarded for participant's IHC.
†IHC assay results awarded the same quick score as UK NEQAS organising laboratory (±1 mark).
‡IHC assay results awarded a quick score that was greater by 2 marks or more than that awarded for UK NEQAS organising laboratory's IHC.
Proportion of 152 cases showing the same* or a greater level of expression** (UK NEQAS organising laboratory's assay)15099%144.105> 0.0001
Proportion of 152 cases showing the same† or a greater level of expression‡ (participating laboratories' assays) 9965% 13.921> 0.0001