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Quality control and quality assurance

 

IHC and ISH techniques are highly specific and reproducible HER2-testing methodologies when performed using standardised and validated protocols. However, such assays may be subject to analytical, pre-analytical and inter-observer variation, contributing to inaccuracies in test results.1,2

 

Strict QC and QA procedures must therefore be followed to ensure optimal identification of patients with HER2-positive disease.


QC recommendations include:1,2
• standardisation of tissue handling, fixation and processing
• standardisation of HER2-testing protocols and reporting
• validation and calibration of all methodologies
• ongoing competency assessment.

All laboratories performing HER2 testing should gain accreditation and participate in an external QA programme, such as that run by the United Kingdom External Quality Assessment Scheme for IHC.3 In addition to national programmes, it is also recommended that HER2-testing laboratories participate in ring studies to assess inter-laboratory consensus and identify factors that may lead to discordant results.4

 

  

Figure 5.4 Principle of a ring study4 (reprinted by permission from Macmillan Publishers Ltd: copyright 2007)

 

 References

 
  1. Carlson RW et al. J Natl Compr Canc Netw 2006; 4 (Suppl 3): S1-S22.
  2. Wolff AC et al. J Clin Oncol 2007; 25: 118-145.
  3. Ellis IO et al. J Clin Pathol 2004; 57: 233-237.
  4. Dowsett M et al. Mod Pathol 2007; 20: 584-591.