Macrothrombocytopenia: Role of Automated Platelet Data in Diagnosis

Purpose Inherited macrothrombocytopenia is an underdiagnosed condition and may result in misdiagnosis and inappropriate management. This research was done to study this condition in a hospital setting. Materials and Methods This study was conducted over 6 months in a teaching hospital. Patients whose complete blood count (CBC) samples were sent to the hematology laboratory were included. Patients were suspected to have inherited macrothrombocytopenia according to pre-defined criteria. Demographic information, automated CBC and peripheral smear examination was carried out. Seventy five healthy individuals and 50 patients with secondary thrombocytopenia were also analyzed. Results Likely inherited macrothrombocytopenia was identified in 75 patients. Automated platelet count in these patients ranged from 26 x 10(boolean AND)9/L to 106 x 10(boolean AND)9/L while MPV ranged from 11.0 to 13.6 fL. There was significant difference (p < .001) in mean platelet volume (MPV) and platelet large cell ratio (P-LCR) amongst patients with likely inherited macrothrombocytopenia, those with secondary thrombocytopenia and the control group. Mean platelet diameter was significantly higher (3.5 +/- 1.1 mu m) in patients with likely inherited macrothromboctopenia compared to those with secondary thrombocytopenia (2.4 +/- 0.7 mu m) and control group (1.9 +/- 0.7 mu m). All patients with suspected inherited macrothrombocytopenia showed abnormal platelet histograms with descending limb in the high volume and red cell zone. Four distinct histogram patterns were identified. Conclusion Inherited macrothrombocytopenia is an underdiagnosed condition. The patient's history, clinical examination, judicious use of automated CBC data including platelet histograms and careful review of the peripheral blood smear are useful tools to suspect this condition.