Assay Failure When Switching Master Mix Products

Symptom

Previously working assay fails completely when switching to different master mix brand; positive controls fail; original master mix works but new one does not despite similar specifications

1. 1 Some assays are particularly sensitive to buffer composition/annealing temperature/primer concentration combinations
2. 2 Different master mixes require different optimization conditions
3. 3 Buffer components differ between manufacturers affecting assay performance
4. 4 Hot Start mechanisms vary between products requiring protocol adjustments

1. 1 Verify all assays in selected master mixes before making changes to large experiment batches
2. 2 Test new master mix on all desired instruments before switching
3. 3 Review instructions provided with each master mix for recommended conditions optimized for the enzyme, Hot Start mechanism and buffer components
4. 4 Re-optimize primer concentration and annealing temperature for new master mix
5. 5 Run new master mix against old master mix side-by-side before launching major experiments

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