IMMUNOHISTOCHEMISTRY, SYNAPTOPHYSIN

What this test checks

Detects synaptophysin, a membrane protein found in neuroendocrine cells. Used together with chromogranin A to confirm neuroendocrine tumours.

Why do people get this test?

Synaptophysin is one of the two primary neuroendocrine markers. Its presence in a tumour confirms neuroendocrine differentiation — critical for identifying carcinoid tumours, small cell carcinomas, and pNETs.

When you should consider this test

• When a tumour is suspected to be a neuroendocrine tumour
• When classifying small cell lung cancer
• As part of neuroendocrine tumour panel (with chromogranin A)

How to prepare

No preparation needed — performed on biopsy or surgical tissue.