Hello guys,

I am struggling with my data analysis in graphpad prism and looking for some help of advanced people.

I did a cell viability assay and plotted my datas in graphpad prism to calculate the IC50 value.

The curves I got look very different from each other and the calculated IC50 value seems not to represent the real values.

I draw some lines in my graph to get an idea of the real IC50 value and compared it to the ones from the table, however for one of my curves it seems much lower as the true value.

When setting the top to the last value of my curve, then it gives me the real value, however when doing so, it also sets this top for the other curve, which gives me then wrong value for this curve.

Is there a way to contraint the top only for one curve?
If you need more information or want to see the curve to get an idea of the problem please text me and I can try to send a image of the graph.

Thank you so much for help