A reciprocal graph to plot the reciprocal serum creatinine over time.

In patients who have a linear decline in renal function over time, plotting the reciprocal serum creatinine versus time has been found to be useful in monitoring renal disease progression and predicting the start of dialysis. Unfortunately, producing such plots is cumbersome because of the inherent difficulties of plotting a reciprocal number on standard graph paper. This technical note presents a graph in which the y-axis is represented as a reciprocal axis. In this manner, one is able to directly plot the serum creatinine over time and must not rely on plotting the reciprocal value. This approach may make the plotting of such data easier for the nephrologist and make this clinical tool more useful.