ELISA blocking & reagent diluent (1% BSA in PBS) recipe
Blocks ELISA plates and dilutes standards, samples and detection antibodies: PBS + 1% BSA.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| BSA (IgG-free, protease-free recommended) | 1 g | 1% |
| 1X PBS | to final volume |
Steps
- Dissolve BSA slowly in PBS.
- Filter through 0.2 µm and store at 4 °C (about a week).
- Blocking: 200–300 µL per well for ≥1 h at room temperature.
Good to know
- Serum/plasma samples show matrix effects; diluting standards in a similar matrix improves accuracy.
FAQ
Can I block with milk?
Yes, except with biotin–streptavidin detection, where milk biotin interferes — use BSA.
This is a widely used standard composition. Amounts depend on the hydrate form and purity of your reagents — check the formula weight (FW) on the bottle and follow your institution's safety rules and the manufacturers' instructions.