In some cases it may be helpful to plot an individual patient’s result (or an entire cohort of patients’ results on a HLC dot plot Figure 11.1
). This is a graph displaying Ig’κ HLC concentrations (x-axis) against Ig’λ HLC concentrations (y-axis), both on logarithmic scales. The limits of the normal reference interval for the Ig’κ/Ig’λ HLC ratio are represented by two parallel lines. Each patient result is represented by a single point. If the Ig’κ/Ig’λ HLC ratio is normal, the result will fall within the normal reference interval. A result that lies outside the normal reference interval is consistent with the presence of a monoclonal intact immunoglobulin.