title: A reference image-based method for optimization of clinical immunohistochemistry.
abstract: OBJECTIVE
  Cold ischaemic and formalin fixation time (CIT and FFT) are considered to be crucial parameters for intralaboratory variation in immunohistochemistry (IHC). Here we describe a new method to optimize IHC, by using control tissue blocks with known pre-analytical history and comparing the IHC outcome with digitized reference slides.
  
  
  RESULTS
  Tissue specimens (two per tissue type) were divided into eight samples, which were subjected to different CIT and FFT. Immunohistochemistry was performed with 34 routinely used antibodies, following standard operating procedures. Relative staining intensity of four sections per slide was scored. Of the antibodies studied, seven were influenced by CIT, 13 by FFT and five by both parameters. IHC protocols were adapted until most sections on the slide showed the same intensity. Changing the antibody dilution for 10 protocols and the antigen retrieval method for six protocols improved the consistency of the IHC staining. Nine protocols could not be optimized. The optimized staining results were compared to reference slides and were found to be of adequate quality.
  
  
  CONCLUSIONS
  It was possible to optimize most IHC protocols by adapting the analytical, rather than the pre-analytical, phase. If global references can be established, this method could decrease interlaboratory variation, preceding standardization of the pre-analytical workflow.
authors: Department of Pathology, Erasmus MC, Rotterdam, The Netherlands.
authors: Marcel
authors: M
authors: Kap
authors: Department of Pathology, Erasmus MC, Rotterdam, The Netherlands.
authors: King H
authors: KH
authors: Lam
authors: Department of Pathology, Erasmus MC, Rotterdam, The Netherlands.
authors: Patricia
authors: P
authors: Ewing-Graham
authors: Department of Pathology, Erasmus MC, Rotterdam, The Netherlands.
authors: Peter
authors: P
authors: Riegman
mesh_terms: D000906:Antibodies / Q000737:chemistry; D015415:Biomarkers / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D003106:Colon / Q000033:anatomy & histology / Q000378:metabolism; D005557:Formaldehyde; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods / Q000592:standards*; D007668:Kidney / Q000033:anatomy & histology / Q000378:metabolism; D014066:Palatine Tonsil / Q000033:anatomy & histology / Q000378:metabolism; D010179:Pancreas / Q000033:anatomy & histology / Q000378:metabolism; D012015:Reference Standards; D012867:Skin / Q000033:anatomy & histology / Q000378:metabolism; D013194:Staining and Labeling / Q000379:methods / Q000592:standards*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D016707:Tissue Fixation / Q000379:methods
chemical_list: D000906:Antibodies; D015415:Biomarkers; D014408:Biomarkers, Tumor; D005557:Formaldehyde
keywords: FFPE; cold ischaemic time; formalin fixation time; immunohistochemistry; interlaboratory variation; optimization; pre-analytical phase