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.

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

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

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