Mountain plot

A mountain plot (or "folded empirical cumulative distribution plot") is created by computing a percentile for each ranked difference between a new method and a reference method. To get a folded plot, the following transformation is performed for all percentiles above 50: percentile = 100 − percentile. These percentiles are then plotted against the differences between the two methods (Krouwer & Monti, 1995; CLSI, 2003).

Required input

  • You can enter variables for two or three laboratory assays.

    In case of three assays, the second and third assay will be compared with the first reference assay.

  • Optionally select a filter to include a subset of cases.

Graph options

  • Plot all data points: show all the data points in the graph.


  • CLSI (2003) Estimation of Total Analytical Error for Clinical Laboratory Methods; Approved Guideline. CLSI Document EP21-A. Wayne, PA: Clinical and Laboratory Standards Institute.
  • Krouwer JS, Monti KL (1995) A simple, graphical method to evaluate laboratory assays. Eur J Clin Chem Clin Biochem 33:525-527. PubMed

See also


Go to Mountain plot.