IMUNOHISTOCHEMISTRY, NAPSIN-A

What this test checks

Detects Napsin-A protein, which is expressed in lung adenocarcinoma and some kidney cancers. Used alongside TTF-1 to confirm lung adenocarcinoma origin.

Why do people get this test?

Napsin-A is a complementary marker to TTF-1 for confirming lung adenocarcinoma. The combination increases diagnostic accuracy, especially when one marker is equivocal — important for targeted therapy selection.

When you should consider this test

• When classifying lung cancer as adenocarcinoma
• When confirming lung origin in metastatic cancer of unknown primary
• As part of lung cancer subtyping panel

How to prepare

No preparation needed — performed on biopsy or surgical tissue.