Clinical significance of IPF% or RP% measurement in distinguishing primary immune thrombocytopenia from aplastic thrombocytopenic disorders.

The diagnosis of primary immune thrombocytopenia (ITP) is based on differential diagnosis. Although the measurement of percentages of reticulated platelets (RP%) by flow cytometry is useful as a supportive diagnostic test, this method is nonetheless a time-consuming, laboratory-based assay. To identify alternative assays that are useful in daily practice, we compared three methods in parallel, IPF% measured by XE-2100 [IPF% (XE), Sysmex Corp.], IPF% measured by new XN-1000 [IPF% (XN)], and RP%. We examined 47 patients with primary ITP, 28 patients with aplastic thrombocytopenia (18 aplastic anemia and 10 chemotherapy-induced thrombocytopenia) and 80 healthy controls. In a selected experiment, we examined 16 patients with paroxysmal nocturnal hemoglobinuria (PNH) to examine the effect of hemolysis. As compared with IPF% (XE), IPF% (XN) showed better within-run reproducibility. The sensitivity and specificity for the diagnosis of ITP were 83.0 and 75.0 % for IPF% (XE), 85.1 and 89.3 % for IPF% (XN), and 93.6 and 89.3 % for RP%, respectively. Examination of PNH patients revealed that hemolysis and/or red blood cell fragments interfered with IPF% (XE) values, but not with IFP % (XN) values. Our results suggest that IPF% measured by XN-1000 may be of comparable value with RP% as a supportive diagnostic test for ITP.

[Effects of anticoagulants and storage temperature on immature platelet fraction % (IPF%) values in stored samples measured by the automated hematology analyzer, XE-5000--utility of CTAD-anticoagulation and room temperature storage].

Measurement of reticulated platelet percentage (RP%) is thought to be a useful marker for differential diagnosis and analysis of platelet kinetics in patients with thrombocytopenic disorders. Two methods are used to detect RP; flow cytometric method and immature platelet fraction (IPF) method using automated hematology analyzers. Although IPF% measured by the automated hematology analyzers is simple and convenient, we already reported that IPF% values were highly fluctuated in stored whole blood sample with EDTA-2K at 4 degrees C day by day. In this study we investigated the stability of IPF% in blood samples obtained from 11 patients with chronic immune thrombocytopenic purpura (ITP) and 19 healthy volunteers using the automated hematology analyzer, XE-5000 (Sysmex) under various storage conditions. EDTA-2K, 3.13% sodium citrate, acid-citrate dextrose solution (ACD), citrate-theophylline-adenosine-dipyridamole solution (CTAD), or sodium fluoride was used as an anticoagulant. When blood samples obtained from healthy subjects were stored at 4 degrees C, IPF% values markedly increased in a time-dependent manner by any anticoagulant examined. On the other hand, there was no significant or only slight difference in IPF% values at room temperature (RT) storage except sodium fluoride. However, in patients with ITP the elevated IPF% values fluctuated widely in EDTA-2K, sodium citrate and ACD-anticoagulated samples even at RT storage. In contrast, IPF% values in CTAD samples stored at RT were highly stable in all patients with ITP up to 4 day storage. These results suggest that the measurement of IPF% by XE-5000 provides quite stable data up to 4 day-storage in ITP patients as well as healthy subjects under CTAD-anticoagulation and RT storage conditions.

Characteristic changes in platelet-large cell ratio, lactate dehydrogenase and C-reactive protein in thrombocytosis-related diseases.

We examined the clinical usefulness of 3 parameters of routine laboratory tests [platelet-large cell ratio (P-LCR), lactate dehydrogenase (LDH) and C-reactive protein (CRP)] in 84 patients with thrombocytosis-related diseases (reactive thrombocytosis, chronic myeloid leukemia, essential thrombocythemia and polycythemia vera). These thrombocytosis-related diseases were characterized using the 3 parameters P-LCR, LDH and CRP as follows: high P-LCR and high LDH in chronic myeloid leukemia; high CRP in reactive thrombocytosis; slightly high P-LCR and high LDH in essential thrombocythemia and polycythemia vera. For essential thrombocythemia and polycythemia vera, levels of P-LCR and CRP were nearly identical, but the LDH level in essential thrombocythemia was significantly higher than in polycythemia vera. These characteristics of P-LCR, LDH and CRP may be useful for simple and very rough differentiation of the thrombocytosis-related disease mentioned above.