Bland and Altman plots. Bland and Altman plots show a large variability between one (1x) and two rounds (2x) of amplification for (A) T1 and (B) T2 with wide 95% limits of agreement of -0.7 to 0.7. The variability within the same amplification method is much smaller for as well (C) 1× as (D) 2x, both with much narrower 95%-limits of agreement of -0.3 to 0.3. No systematic bias was found. As an example, only Cy5 is shown here. T1-1x, tumor – one round of amplification; T1-2x, tumor – two rounds of amplification; T2-1x, duplicate tumor – one round of amplification; T2-2x, duplicate tumor – two rounds of amplification; dotted line, 95%-limits of agreement.