Differences in automated depolarization patterns of Plasmodium falciparum and P. vivax malaria infections defined by the Cell-Dyn® CD4000 haematology analyser

• Published in: Transactions of the Royal Society of Tropical Medicine and Hygiene 2003, Vol.97 (1), p.71-79
• Main Authors: FAWZI, Zainab O, FAKHRO, Naila A, NABHAN, Randa A, ALLOUECHE, Ali, SCOTT, Colin Stephen
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Eosinophils - metabolism; Eosinophils - parasitology; Hemeproteins - metabolism; Human protozoal diseases; Humans; Infectious diseases; Malaria; Malaria, Falciparum - diagnosis; Malaria, Vivax - diagnosis; Malaria, Vivax - parasitology; Medical sciences; Microscopy, Polarization - methods; Monocytes - metabolism; Monocytes - parasitology; Parasitic diseases; Parasitology - methods; Plasmodium falciparum - isolation & purification; Plasmodium vivax - isolation & purification; Protozoal diseases; Tropical medicine
• ISSN: 0035-9203; 1878-3503
• DOI: 10.1016/S0035-9203(03)90029-0

Of 1014 samples submitted for full blood count analysis and malaria screening, 854 were designated malaria-negative by blood film microscopy, 79 were unequivocally identified as Plasmodium vivax and 81 as P. falciparum. All samples were additionally analysed with the Abbott Cell-Dyn CD4000 haematology instrument, and leucocyte differential plots of 90 degrees polarized vs. 90 degrees depolarized (NEU-EOS plot) and 90 degrees depolarized vs. 0 degree light (EOS I plot) scatter were specifically examined for abnormal depolarization patterns. Depolarization pattern types were correlated with microscopy (species) results, and these correlations were consolidated by polymerase chain reaction analysis. All 854 microscopically-designated malaria-negative samples showed a type 1 (normal) CD4000 depolarization pattern. Abnormal pattern types 2, 3a and 3b were entirely restricted to one of the two malaria categories. Plasmodium falciparum malaria showed two CD4000 pattern types only; a 'normal' type 1 pattern was seen in 36/75 (48%) cases and the remaining 39 cases were all abnormal pattern type 3a. In contrast, most (79/85) P. vivax malaria cases showed a distinctive clustered EOS I population (types 2 and 3b patterns) that was not seen with P. falciparum. Automated depolarization analysis provides an effective means of detecting malaria-associated haemozoin, and the patterns of intracellular haemozoin further appear to provide species differentiation between P. falciparum and P. vivax.