I read with interest a recently published article from Tripodi et al1 on the subject of positive controls for immunohistochemistry. The importance of the subject cannot be overemphasised, as to this day, there is no standardisation of controls in diagnostic immunohistochemistry. This includes both, positive and negative controls. Similarly, the terminology in this area is also lacking standardisation. The lack of standardisation in this area prompted the Canadian Association of Pathologists to issue at least some recommendations for consideration for best practices in diagnostic immunohistochemistry.1 Ours, like many other professional organisations, continues to be challenged with highly complex issues in this area of pathology practice.

Tripodi et al2 describe a novel approach to ‘internal controls’, and suggest replacing external controls with internal controls. This approach re-emphasises the advantages of having external controls on the same slide as the patient's …