Evaluation of the immature platelet fraction contribute to the differential diagnosis of hereditary, immune and other acquired thrombocytopenias.

The differential diagnosis of immune (ITP) and hereditary macrothrombocytopenia (HM) is key to patient management. The immature platelet fraction (IPF) represents the subset of circulating platelets with higher RNA content, and has been shown to distinguish hypo- from hyperproliferative thrombocytopenias. Here we evaluated the diagnostic accuracy of IPF in the differential diagnosis between HM and other thrombocytopenias in a population of patients with post-chemotherapy thrombocytopenia (n = 56), bone marrow failure (n = 22), ITP (n = 105) and HM (n = 27). TPO levels were also measured in HM and ITP matched for platelet counts. Platelet counts were similar in all patient groups. Higher IPF values were observed in both ITP (12.3%; 2.4-65.6%) and HM (29.8%; 4.6-65.9%) compared to hypoproliferative thrombocytopenias. IPF values were also higher in HM compared to ITP, yielding a diagnostic accuracy of 0.80 (95%CI 0.70-0.90; P < 0.0001) to distinguish these two conditions. Intra- and inter-assays reproducibility of IPF in HM patients revealed that this is a stable parameter. In conclusion, IPF is increased in HM compared to both ITP and other thrombocytopenias and contributes to the differentiation between ITP and HM. Further studies are warranted to understand the biological rationale of these findings and to its incorporation in diagnostic algorithms of HM.

Evaluation of PCR in the diagnosis of canine leishmaniasis in two different epidemiological regions: Campinas (SP) and Teresina (PI), Brazil.

SUMMARY Using the polymerase chain reaction (PCR) test for diagnosis of canine leishmaniasis has greater sensitivity and specificity than culture and visualization of the parasite. This study compares PCR for the diagnosis of the genus and species of Leishmania with serological techniques used for the control of canine visceral leishmaniasis (CVL) in Brazil, considering two regions. We analysed peripheral blood samples collected from 195 dogs in the Campinas (SP) and Teresina (PI) regions. ELISA was performed as a serological method and PCR was performed using specific primers for the genus Leishmania spp. and the species Leishmania chagasi. In Campinas, a greater sensitivity of PCR (88.24%) (P = 0.0455) compared to Teresina (14.71%) (P < 0.0001) was observed, and an agreement was observed for Cohen's kappa index (0.9096). Both PCR and ELISA showed discordance for sensitivity (Campinas 100%, Teresina 21.74%), specificity (Campinas 30.77%, Teresina 100%), positive predictive value (Campinas 68.97%, Teresina 100%), negative predictive value (Campinas 100%, Teresina 37.94%) and Cohen's kappa index (0.1238). This study confirms the importance of PCR in analysis of the canine reservoir, and as an effective method for the detection of active and recent infection.