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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)
Cell Signaling Technology ★ 95
Immunohistochemistry Protocol for Paraffin embedded Tissue Sections
"Official CST IHC protocol video for paraffin-embedded tissue sections directly addresses the technique and deparaffinization steps central to this failure case"
Bilibili (China-Accessible Mirrors) ★ 92
Immunohistochemistry on Paraffin-Embedded Sections (CST Demo)
"CST-based step-by-step demonstration of IHC on paraffin-embedded sections explicitly covers antigen retrieval and deparaffinization procedures that prevent patchy background staining"
Cell Signaling Technology ★ 78
Better IHC Step 1: Antigen Retrieval
"Focused educational series on antigen retrieval optimization for IHC, directly relevant to preventing inadequate deparaffinization artifacts and achieving uniform staining"
Source: cellsignal.com ↗
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