Final answer:
Malaria parasites are identified by reviewing stained blood smears under a microscope, looking for purple-stained ring shapes that indicate the presence of Plasmodium falciparum.
Step-by-step explanation:
Malaria parasites are identified in the hematology laboratory primarily through the microscopic examination of blood smears. A stained blood smear slide is reviewed under a microscope using an oil immersion lens, often at 100x magnification. Plasmodium falciparum, the causative agent of malaria, can be seen infecting red blood cells, sometimes appearing as purple ring-shaped figures on the smear (Figure 13.16).
For diagnosing malaria, technicians search for signs of trophozoite development within the red blood cells, as well as for extracellular merozoites. Such a smear would be scanned until 100 cells have been counted to estimate the level of parasitemia. Additionally, there are other diagnostic methods, such as rapid EIA assays which can detect Plasmodium antigens or enzymes.
Furthermore, in some cases, diagnostic tests employ the use of specific genetic probes that can bind to and identify Plasmodium DNA in a sample. These probes, which can be chemically synthesized and radiolabelled, allow for the identification of malaria at the molecular level.
The comprehensive approach to malaria detection helps ensure accurate diagnosis and appropriate treatment, which may include drugs like chloroquine, atovaquone, artemether, and lumefantrine, despite the growing issue of drug resistance.
Counting infected cells within 100 red blood cells estimates parasitemia levels. Additionally, rapid EIA assays and genetic probes assist in the diagnosis by detecting antigens, enzymes, and DNA specific to malaria.