A-223 Early Recognition of Thrombotic Thrombocytopenic Purpura Using the Mindray BC-6800Plus Hematology Analyzer in a Low-Incidence Setting in Peru: A Case Report

Abstract

Background The High-Complexity Hospital Virgen de la Puerta – EsSalud La Libertad in Trujillo, Peru, is a specialized center for the diagnosis and management of complex medical conditions. Thrombotic Thrombocytopenic Purpura (TTP) is a very rare and life-threatening hematologic disorder, with an estimated global incidence of 4–5 cases per million people per year. There are no official records that accurately detail the incidence of TTP in Trujillo or nearby areas. The diagnosis of TTP is primarily based on clinical suspicion of thrombotic microangiopathy, confirmed by the triad of severe thrombocytopenia, microangiopathic hemolytic anemia (with schistocytes), and ADAMTS13 enzyme activity below 10%. Methods A 32-year-old male patient from Chimbote, presented with petechiae on the arms and back, accompanied by general malaise. His Glasgow Coma Scale score was 15. Later, scleral and palmar jaundice appeared, along with nausea and vomiting. The patient subsequently became encephalopathic, with incoherent speech. A whole blood sample was collected in a K2-EDTA tube for complete blood count analysis using the Mindray BC-6800Plus hematology analyzer. Scattergrams, histograms, and cytograms were evaluated, and a peripheral blood smear (PBS) was reviewed. Other biochemical analyses were also performed as part of the evaluation protocol. Results Liver and spleen were normotrophic. Laboratory findings: Coagulation times were within normal limits, and d-dimer was 0.89 µg/mL. Blood group and Rh factor: A1 Rh positive, and direct Coombs test was negative. Total bilirubin 8.58 mg/dL, direct bilirubin 0.58 mg/dL, glucose 126 mg/dL, creatinine 0.96 mg/dL, urea 43 mg/dL, LDH 3,337 IU/L. Hematocrit 22.7%, hemoglobin 7.8 g/dL, platelets 7,000/mm³, and IMG 3%. PBS revealed anisocytosis 1+, polychromatophilia 3+, schistocytes 3+, and spherocytes 1+. Fourteen normoblasts per 100 leukocytes were observed. Reticulocyte count was 17%, RBC fragments 1.21%, and reticulocyte production index (RPI) 4.1. Analyzer alarms included: Abnormal lymphocytes/blasts, immature granulocytes, presence of NRBC, lymphopenia, anemia, RBC fragments, abnormal RET scattergram, reticulocytosis, abnormal platelet histogram, and thrombocytopenia. The DIFF scattergram showed high-fluorescence cells above neutrophils compatible with IMG and low-fluorescence cells below lymphocytes, which correlates with NRBC. In the RET scattergram, an increase in fragments and immature red blood cells with intermediate to high fluorescence corresponding to reticulocytosis was observed. Peripheral smear review confirmed the presence of schistocytes and marked thrombocytopenia. Conclusion This case highlights the importance of having diagnostic tools capable of identifying unlikely clinical conditions in small localities such as this city in Peru. The Mindray BC-6800Plus analyzer, which uses optical and fluorescence-based methodology for cell counting, was of critical value, especially in differentiating platelets from schistocytes. In addition, the elevation of research-use-only parameters, FRC% and RPI, provided by the analyzer, together with thrombocytopenia, increased the suspicion of TTP before PBS review and before the confirmatory ADAMTS13 test, which is not available in Peru, making it necessary to send it abroad, which means time and financial resources.