Batch-to-batch variation of the mean staining intensity of HER2 can be noted visually on the consecutive tissue control sections arranged on computer monitor. Nine consecutive HER2 IHC 2+ spot images are ordered from left to the right and down. Variable brown colour intensity can be noted.
Laurinavicius et al. Diagnostic Pathology 2013 8(Suppl 1):S15 doi:10.1186/1746-1596-8-S1-S15