Hi,

First, does your sample readout raw value exceed the standard range? If your sample values are higher than the readouts from your standard linear range, you cannot determine the sample value.

Your kit should have a sample dilution buffer. In principle you can dilute your sample as much as is needed to get the signal to the level that corresponds the standard linear range. IF you are unsure, just make a dose response of dilutions.

Thank you for your answer.

Yes my samples values are largely exceeding the standard range (samples values= 12000 pmol/l, standard maximum range= 2000 pmol/). That's why i want to dilute my samples. My other issue is the diluent, wich one can i use for this method ? scine the kit doesnt contains a diluent . Is it BSA or others ?

I would be hesitant to suggest you a diluent buffer for the assay. They differ greatly between applications and assays. Your best choice is to either provide the kit information here (name, manufacturer etc.) or to contact the kit manufacturer or distributor directly for further instructions.

If you use non-optimised dilution buffer, you may introduce other problems that impact the linearity of your detection. Again, you can of course test this. If you make a dilution series of your sample in a home-made buffer and the slope is identical to your standard curve, you are pretty close to what you need.

A typical ELISA diluent buffer that I have used a lot would look like:

Phosphate buffered saline at pH 7.4 with 1% BSA (w/v) as carrier/blocking protein and a detergent such as Tween20 (0.05% v/v)to reduce aspecific binding.

A RIA dilution buffer I just found by googling would look like

0.1% Triton X-100,0.1% BSA, 0.01% sodium azide (NaN3), 0.05M NaCl, and 0.1M sodium phosphate buffer (pH 7.4).

Best

Juha

Thank you so much Mr Juha for your help. I will try it, hope it will work.