White Spots in Center of Normal Spots (Donut Pattern)

Symptom

Spots develop with white or lighter centers surrounded by darker rings, creating a donut-like appearance. This is more common with enzymatic detection methods.

1. 1 Coating antibody concentration insufficient for optimal capture
2. 2 Issues during the coating step affecting antibody distribution
3. 3 For fluorescence detection: antibody concentrations too low

1. 1 Increase coating antibody concentration through optimization
2. 2 Evaluate spot quality to determine if capture antibody dilution or coating step has issues
3. 3 For fluorescence detection: increase antibody concentrations for both capture and detection

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