[Relationship between reticulated platelets and megacaryocyte number in thrombocytopenic patients].

Background And Introduction: Marrow aspiration is a test that helps the pathogenic diagnosis of thrombocytopenia. Our goal was to analyze the correlation between reticulated platelets (RP) values in peripheral blood with megakaryocytic number in bone marrow in a group of thrombocytopenic patients.

Patients And Methods: Prospective observational study in thrombocytopenic patients, between June 2002 and June 2005. RP determination was performed by flow cytometry using whole blood. We used a monoclonal anti-glycoprotein-IIIa antibody (CD61PerCP) for platelet identification and orange thiazole (Retic-count) as platelet mRNA stain. Marrow study was conducted by marrow aspiration.

Results: RP were measured in 54 thrombocytopenic patients with bone marrow study. Three were excluded from the study. Thirty-two patients had central thrombocytopenia with diminished megakaryocytes (MK) and/or dysplasia, mean of RP 9.5% (CI 95%:5.6%-13.4%). Thirteen patients had high MK,mean of RP 25.7%(CI 95%:13.1%-38.3%). Six patients had normal MK, mean of RP 13.6% (CI 95%:0.6%-26.8%). There were differences between the group of increased MK and the group of central thrombocytopenias (p=0001). A value of RP>or=11% showed a sensitivity of 70% and specificity of 81% for the diagnosis of marrow aspirate with increased MK.

Conclusions: RP are an indirect marker of megakaryocyte number in bone marrow. A value of RP>or=11% in patients with thrombocytopenia, especially with an acute onset, would indicate regenerative thrombocytopenia, while in the presence of low levels of RP a marrow aspiration should be performed.