Enzyme immunohistochemistry explained

A pathologist prepares a thin section from a tissue sample, often obtained through biopsy. Antibodies are applied to the section. If an antibody recognises its matching protein, an enzyme-linked label produces a coloured reaction at that location. The pattern and strength of staining are interpreted with the tissue’s appearance and the clinical context.

The test can help classify a tumour, distinguish similar-looking conditions, or identify markers that affect treatment choices. A stain is one part of the pathology report; it is not a stand-alone description of a person’s health.

Ask which marker was tested, whether the result was positive, negative, weak, or strong, and how the finding changes the diagnosis or treatment plan. Results can depend on the sample and the method used, so your clinician may recommend additional stains, molecular tests, or review by another pathologist. Keep the biopsy report and ask for an explanation of unfamiliar terms rather than interpreting a stain in isolation.

The laboratory test itself does not usually create an urgent symptom. Contact the clinical team promptly for worsening pain, redness, swelling, drainage, fever, or bleeding after a biopsy. Seek emergency help for severe bleeding, fainting, or trouble breathing. Arrange follow-up to discuss the report when results are available, particularly if further testing has been recommended.

Ask what the stain detects, why it was selected, whether the sample was adequate, and whether other tests are needed. Ask how the result fits with the biopsy findings and what decision it supports.