Inconsistent Antigen Retrieval Results

Symptom

Antigen retrieval (AR) performance varies unpredictably across sections and targets. Harsh AR needed to recover signal suggests overfixation. Epitope accessibility inconsistent even with standardized protocols.

1. 1 Overfixation requiring harsh retrieval to undo damage
2. 2 Fixation temperature and duration variability
3. 3 Epitope-specific sensitivity to fixation chemistry
4. 4 Using AR as default rather than optimizing fixation first
5. 5 Section thickness variability affecting retrieval penetration

1. 1 Reevaluate and minimize fixation duration and temperature
2. 2 Test lighter fixation conditions (e.g., 2% PFA in 0.1 M sodium acetate pH ~6)
3. 3 Try milder retrieval buffer if harsh conditions currently required
4. 4 Optimize blocking and washing before escalating to aggressive AR
5. 5 Use AR sparingly and purposefully, not as routine default
6. 6 Document fixation parameters and AR conditions for reproducibility

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