HISTOPATHOLOGY SPECIAL STAIN: AMYLOID (CONGO RED)

What this test checks

A special stain that highlights amyloid protein deposits in tissue under polarised light, producing a characteristic 'apple-green' birefringence. Used to diagnose amyloidosis — a condition where abnormal proteins accumulate in organs.

Why do people get this test?

Amyloidosis can damage the heart, kidneys, liver, and nerves silently. Congo red staining on a biopsy provides definitive diagnosis, allowing treatment to begin before irreversible organ damage occurs.

When you should consider this test

• When amyloidosis is suspected as a cause of organ dysfunction
• When investigating unexplained kidney failure, heart failure, or peripheral neuropathy
• When a fat pad or rectal biopsy is taken to screen for systemic amyloidosis

How to prepare

No preparation needed — performed on existing tissue samples.