|Ahead of print
Not all blast flags in hematology analysers are leukemia - think malaria!
Jayashree D Kulkarni, Rajesh Singh, PS Pramod
Department of Pathology and Laboratory Medicine, Columbia Asia Referral Hospital - Yeshwanthpur, 26/4, Brigade Gateway, Beside Metro, Malleswaram West, Bengaluru, Karnataka, India
Jayashree D Kulkarni,
Department of Pathology and Laboratory Medicine, Columbia Asia Referral Hospital - Yeshwanthpur, 26/4, Brigade Gateway, Beside Metro, Malleswaram West, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
A 36-year-old man presented with a one-week history of fever. Laboratory investigations showed thrombocytopenia (8 × 10^3/μL) and abnormal kidney function tests (sodium = 124 [136–144 mmol/L]; chloride = 92 [101–111 mmol/L]; urea = 119 [17–43 mmol/L], and creatinine = 1.86 [0.9–1.3 mg/dL]).
The hematology analyser, Beckman-Coulter LH 780 showed a monoblast flag. However, a sharp peak in the non-white blood count (WBC) area of the WBC histogram and corresponding red dots on the scatter-plot [Figure 1]a made us suspect malarial parasitemia. The malarial rapid diagnostic test (Avantor BeneSphera™) was positive [Figure 1]b and peripheral smear showed ring forms and gametocytes of Plasmodium falciparum [Figure 1]c. Anti-malarial therapy was initiated immediately.
|Figure 1: (a) Histogram and scatter plot. Single black arrow monoblast flag. Double black arrows red dots in the nonWBC area in the scatter plot. Triple black arrows sharp peak in the nonWBC area of the WBC histogram. (b) Positive malarial rapid card test: Red arrow positive band indicating Plasmodium falciparum parasitemia. (c) Peripheral smear showing ring forms and gametocyte of Plasmodium falciparum: White arrows ring forms of Plasmodium falciparum. Blue arrow gametocytes of Plasmodium falciparum|
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Different automated analysers have specific indicators for malarial parasitemia. In LH 780, parasitized red blood cells (RBC) produce a sharp peak in the WBC histogram and cluster of red dots in the scatterplot. Platelet clumps and nucleated RBC may also result in similar peaks and should be excluded. The monoblast flag reflects an increased volume of activated monocytes. Care should be taken in its interpretation, as it can also be seen in dengue, infectious mononucleosis and myeloid leukemia, conditions which are often also associated with thrombocytopenia.
This case is a splendid illustration of how a sharp peak in the WBC histogram and a monoblast flag (which was false positive) in a patient with a fever with thrombocytopenia helps make a life-saving diagnosis of malaria.
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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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| » References|| |
Campuzano-Zuluaga G, Hänscheid T, Grobusch MP. Automated haematology analysis to diagnose malaria. Malar J 2010;9:346.
Singh A, Narang V, Sood N, Garg B, Gupta VK. Malaria diagnosis using automated analysers: A boon for hematopathologists in endemic areas. J Clin Diagn Res 2015;9:EC05-8.