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Immunohistochemistry (CST Guide) moderate

Spotty or Uneven Background Staining Pattern

Symptom
Staining pattern shows irregular, patchy, or spotty background with uneven distribution across tissue sections, indicating technical artifacts rather than biological variation.
Common Causes
  1. 1 Inadequate deparaffinization leaving paraffin residue in patches on tissue
  2. 2 Tissue sections partially dried during staining protocol due to insufficient liquid coverage
  3. 3 Old or degraded xylene used for deparaffinization step
Solutions
  1. 1 Repeat experiment with new tissue sections using fresh xylene for complete deparaffinization
  2. 2 Ensure tissue sections remain fully covered in liquid throughout all incubation and washing steps
  3. 3 Replace xylene stock if older than recommended shelf life; use high-quality fresh xylene
Related Video (3)
Bilibili (China-Accessible Mirrors) ★ 95
Immunohistochemistry on Paraffin-Embedded Sections (CST Demo)
"Direct CST IHC protocol demonstration on paraffin-embedded sections covering the complete workflow including deparaffinization, the critical step where the reported failure originates."
Cell Signaling Technology ★ 88
Immunohistochemistry Protocol for Paraffin embedded Tissue Sections
"Official CST immunohistochemistry protocol for paraffin-embedded tissue sections with access to comprehensive troubleshooting guide addressing background staining issues."
Cell Signaling Technology ★ 72
Better IHC Step 1: Antigen Retrieval
"Focused video on antigen retrieval step which directly follows deparaffinization and can help identify whether inadequate deparaffinization contributed to uneven staining patterns."
Source: cellsignal.com ↗
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