The haematological emergency - Severe thrombocytopenia - Calendar 2008 month 5

Author(s): H. Diem (1), R. Hinzmann, F. Forstreuter (2)
Institution(s): (1) Würmtal-Labor, 82131 Gauting; (2) Sysmex Europe GmbH, Norderstedt - Germany
References: The Sysmex Scientific Calendar 2008;
Photos and text: Heinz Diem, MD; text: Rolf Hinzmann, MD, PhD; Frauke Forstreuter, PhD
Last change of this image collection: 2008/01/01

Thrombocytopenia is defined by a platelet count below the lower limit of the reference interval (140,000/µL). The lower the platelet count, the higher the risk of bleeding. At concentrations below 10,000/µL the danger of spontaneous bleeding is so imminent that (with few exceptions like in TTP) platelet concentrates will be administered. The decision on the therapeutic measures requires clinical information (age, underlying disease, risk factors etc.) as well as information about planned interventions (surgery, punctures etc.). In this context the measurement of the immature platelet fraction (IPF) can give useful information on whether or not normal or even elevated thrombopoiesis occurs in the bone marrow.

In the reticulocyte channel of the haematology analysers SYSMEX XE-5000 and XE-2100 the immature platelet fraction (IPF) can be distinguished from the mature platelet fraction. In patients with thrombocytopenia an increase of IPF above the reference interval (1.1-6.1%) usually indicates intact thrombopoiesis, and the low platelet count is most likely due to increased platelet consumption. The IPF value in this example is 35.8%.

Thrombocytopenia (45,000/µL) and platelet anisocytosis as an indication of idiopathic thrombocytopenic purpura (ITP) in a child after viral infection. IPF in this case was 18.3%.

Platelet satellitosis: Platelets adhere to granulocytes, induced by the anticoagulant EDTA.

Thrombocytopenia and detection of cytoplasm fragments from monoblasts in AML-M5A. Due to their similar size the cytoplasm fragments can produce a falsely elevated platelet count in impedance measurement on certain haematology analysers. Here the initial count was 32,000/µL. The correct platelet value was obtained from the optical channel; it was 7,000/µL. Cytoplasm fragments (Z) and a platelet (T) are marked.