Correlation between parasitaemia and fluorescence emission. PG (A) and SGI (B) fluorescence detected in Plasmodium falciparum infected erythrocytes at different parasitaemias. A serial fold dilution of synchronized infected culture (15% mature ring stage) with non-infected erythrocytes was used. Results are shown for haemoglobin non-depleted samples (black square), and haemoglobin depleted samples in the absence (white square) or presence (white circle) of 2% Triton X-100. Bars indicate the standard deviation of the mean from three independently processed samples.