Peroxidase Immunohistochemistry: What to Know

A pathologist places thin sections of tissue on a slide and applies an antibody designed to bind a particular protein. A peroxidase enzyme linked to the detection system creates a visible colour where that binding occurs. The pattern and strength of staining are interpreted with the tissue appearance and other tests.

This method can help classify a tumour, suggest where it began, or identify a marker relevant to treatment. A stain is not a diagnosis on its own: the result is read alongside the biopsy findings, clinical history, and imaging.

Ask which marker was tested, whether the result was positive, negative, or indeterminate, and how much tissue was available. Some results need a control stain, repeat testing, or a second marker panel. Request a plain-language explanation of how the finding changes diagnosis or treatment, and ask whether another pathology review is appropriate.

The laboratory stain itself does not usually cause symptoms because it is performed on tissue already collected. After a biopsy, seek prompt advice for increasing redness, swelling, drainage, fever, uncontrolled pain, or bleeding from the sampling site. Follow the specific aftercare instructions given by your clinical team.

Ask what the stain is intended to detect, whether it supports a particular tumour type, and whether the sample was adequate. Discuss how the result fits with the rest of the pathology report, whether additional testing is needed, and when the complete interpretation will be available.