Quantitation of the Percentage of Reticulated Platelets to Diagnose the Cause of Thrombocytopenia / 대한진단검사의학회지

BACKGROUND: Since reticulated platelets (RP), known to be newly released from megakaryocytes in the bone marrow into the blood, contain RNA in their cytoplasm, we can detect them by staining RNA remnants with fluorescent dyes and performing flow cytometric analysis. We attempted to search for the best conditions in quantitating the percentage of RP (RP%) to identify causes of thrombocytopenia. METHODS: The RP% were measured on venous blood samples collected in EDTA from 63 normal controls and 48 thrombocytopenic patients. The thrombocytopenic patients were divided into two groups according to the causes: hypoplastic and destructive. The RP% was determined by a flow cytometric analysis with anti-CD41a and thiazole orange (TO) as a fluorochrome. RESULTS: In patients with their platelet count less than 50 x 10(9)/L, the RP% of two patient groups showed a significant difference. The RP% and platelet count were correlated directly in the hypoplastic group, but inversely in the destructive group. According to the results of ROC curve, the best conditions in quantitating RP% to identify the cause of thrombocytopenia was to apply a 2% threshold of TO positivity among gated platelets; its sensitivity and specificity were 93.3% and 83.3%, respectively. w CONCLUSIONS: The RP% is considered to be a good marker for differentiating destructive from hypoplastic thrombocytopenia and monitoring of the destructive thrombocytopenic patient having normal bone marrow such as idiopathic thrombocytopenic purpura. For the accurate measurement of the RP%, the condition of 2% TO threshold is considered to be appropriate.

Diagnostic Value of Reticulated Platelet in Thrombocytopenia

PURPOSE: We performed this study to determine the diagnostic significance and useful cut-off value of reticulated platelet, which can be used for discriminating the destructive thrombocytopenia from underproductive thrombocytopenia. METHODS: We evaluated 37 patients with thrombocytopenia who were admitted to the Wonju christian hospital from March to July, 1995. All patients were evaluated with bone marrow megakaryocyte count. We divided them into two groups, group 1 was consisted of underproductive thrombocytopenic patients and group 2 was consisted of destructive thrombocytopenic patients. We measured the peripheral blood reticulated platelet count by FACScan flowcytometry after thiazole orange staining. RESULTS: 1) Among 37 patients, underproductive group consisted of 21 patients and destructive group consisted of 16 patients. 2) There was no significant difference in platelet count between two groups (41.7 31.8x109/L vs. 41.0 29.1x109/L). 3) Destructive group showed higher reticulated platelet count than underproductive group (7.7 3.7% vs. 19.1 11.1% : p<0.01). 4) Ideal cut-off value of reticulated platelet count for the discrimination of two groups was 11%. Its sensitivity and specificity were 88% and 95%, respectively. CONCLUSIONS: We suggest that reticulated platelet count is closely correlated with thrombopoiesis of bone marrow. The measurement of reticulated platelet can be a simple and useful diagnostic tool to discriminate destructive thrombocytopenia from underproductive thrombocytopenia.