Detection of haematoparasites using quantitative buffy coat analysis tubes

Use of buffy coat thick films in detecting malaria parasites in patients with negative conventional thick films

“…Earlier study [6] showed that malaria parasites could be concentrated using centrifugation of blood in capillary tube coated with EDTA and acridine orange. The principle of QBC was that infected red blood cells appeared to be less dense than uninfected ones, and concentrate primary within the zone at the interface, a small 1-2 mm region near the top of RBC column, i.e.…”

“…Centrifused blood film was found to be superior to conventional blood film since it included both QBC and blood smear principles. Buffy coat thick film might be easier to examine than buffy coat thin film [6] since red blood cells in buffy coat thin film were dense due to blood centrifugation.…”

“…Thirty six uncomplicated falciparum malaria patients were included in the study. Inclusion criteria were as follows: 1) either male or female; 2) admitted to hospital for 28 days of follow-up after antimalarial treatment; 3) age>15 years; 4) on admission day, pretreatment, microscopically confirmed positive for asexual stage of Plasmodium falciparum parasites by Giemsa stained thick and thin films; 5) received artemisinin combination therapy (ACT) without primaquine after confirmed diagnosis; 6) had no history of antimalarial therapy during 1 month prior admission; and 7) provided fingerprick blood samples, before admission and every 6 hours after ACT treatment until thick films showed negative for parasites, then thick films were conducted daily until discharged from the hospital. If the patients had reappearance of parasitemia, fingerprick blood films were repeated again every 6 hours.…”

A comparison of thick smears, QBC Malaria, PCR and PATH Falciparum Malaria® Test Trip inPlasmodium falciparumdiagnosis

“…Microscopic examination of blood smears remains the method of choice for diagnosing malaria. Newer technologies that have been evaluated include the polymerase chain reaction PCR (Barker et al, 1992; Mc Laughlin et al, 1987), the QBC malaria assay (Levine et al, 1989), assays detecting the Plasmodium falciparum histidinerich protein 2 (PfHRP-2), a water soluble protein released from parasitized erythrocytes (Howard et al, 1986; Parra et al, 199D-These related assays include the PATH falciparum malaria®, a dipstick antigen capture assay developed by PATH (Seattle, USA). The purpose of this study was to evaluate the performance and use of the PATH Falciparum Malaria® Test Trip for the diagnosis of Plasmodium falciparum malaria compared to three other P. falciparum diagnostic assays, Thick smear microscopy, QBC and PCR.…”

Semi-nested, multiplex polymerase chain reaction for detection of human malaria parasites and evidence of Plasmodium vivax infection in Equatorial Guinea.

“…5,6 To overcome the limitations of the conventional microscopic diagnosis, several methods have been used. These include 1) the staining of parasite DNA and RNA with acridine orange (e.g., the quantitative buffy coat method in capillary tubes [QBC]; Becton-Dickinson, Franklin Lakes, NJ) or staining of thick and thin blood films with this dye; [7][8][9] 2) methods based on the detection of the activity of various enzymes (e.g., lactate dehydrogenase); 10 3) a rapid antigen capture assay that detects circulating P. falciparum histidinerich protein-2 (ParaSightF dipstick tests; Becton-Dickinson); 11,12 4) serologic tests (immunofluorescence assay, ELISA, indirect hemagglutination assay) used mainly in nonimmune individuals or in epidemiologic studies; and 5) methods using radioactive or nonradioactive DNA probes for the detection of parasites, or a direct polymerase chain reaction (PCR). [13][14][15] At present, various studies using the PCR have been reported for malaria diagnosis of the four species of Plasmodium that infect humans in different field conditions (blood sample collection, DNA template preparation and PCR assay).…”