Effect of haemoglobin on fluorescence emission. A) Fluorescence emission of SYBR®Green I (solid bars) and PicoGreen® (empty bars) of 1 μg/mL DNA, (485/2.5 nm excitation, 528/2.5 nm emission) in the presence of different amounts of red blood cells. The inset shows the fluorescence signal at 485/15 nm excitation and 528/15 nm emission. Discontinuous bars indicate off-scale fluorescent reading. Fluorescence at 0% haematocrit was obtained from a 1 μg/mL solution of λDNA in culture medium. B) Absorption spectrum of red blood cell lysates.