What should you know about TSA immunohistochemistry?

Immunohistochemistry uses an antibody to recognise a selected protein in prepared tissue. In TSA, an enzyme linked to the detection system deposits signal-producing molecules close to that target, strengthening the visible stain.

This can help a pathologist examine markers that are present in small amounts or support multiplex staining, where several markers are assessed in the same tissue section. The method is a way of detecting tissue features; it is not itself a cancer diagnosis.

TSA staining is usually performed on tissue already collected during a biopsy or another procedure. It does not normally require a separate appointment or injection. The laboratory selects controls and compares the staining pattern with the clinical and microscopic findings.

When you receive a pathology report, look for the marker name, whether staining was detected, where it appeared in the cells, and the pathologist’s interpretation. A result should be read alongside the biopsy findings rather than in isolation.

The stain itself does not cause symptoms because it is performed on tissue outside your body. Contact your clinical team if the biopsy site becomes increasingly red, swollen, painful or draining, or if you develop fever. Seek urgent care for heavy bleeding or severe breathing difficulty after a procedure.

Ask which marker was tested, why it was selected, whether the sample was adequate, how the result changes the diagnostic picture, and whether another stain or test is needed. Request an explanation of terms such as positive, negative, intensity and localisation in your report.