Best blocking reagent ?

Michael R. Thompson Mike.Thompson at
Thu Jun 29 14:34:36 EST 2000

We have used the following , with good results for antibodies raised against
peptide-BSA conjugates:

1% PVP40 (polyvinylpyrrolidine, mol.wt. 40,000 ave; Sigma cat. # PVP-40)
0.05% Tween 20 (blotting grade)
0.1 mM Thimerosal (antimicrobial; Sigma T-5125)
dissolved in Tris-buffered saline.

Hope this helps!

Svend Kjaer wrote in message <395B44A8.7D49D99E at>...
>Dear all,
>I would like to hear of some with alternative suggestions for efficient
>blocking reagents for ELISA.
>Most often I used skimmed milk powder in PBS and that works like a charm
>with a very low background. Alternatively, I go for BSA, but that gives
>a somewhat higher background.
>I would like to have a very low background, yet avoid the use of milk
>powder, which contains non-defined amounts of Calcium as the ELSIA
>supposedly assay is calcium-dependent
>Therefore, are there any alternatives to BSA in providing good blocking
>of non-specific binding ??

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