International journal of laboratory hematology
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Thromboelastography (TEG) is a potentially useful tool but analysis within 4-6 min of collection imposes limitations on its use and access. The use of citrate blood tubes potentially increases the time frame for processing specimens. There is, however, limited research on the stability of citrate specimens, timing of processing and the accuracy of TEG results. ⋯ Furthermore, progressive changes in TEG parameters such as decreasing R were suggestive of a trend toward hypercoagulability of the specimens. Processing of kaolin-activated citrate TEG specimens can begin as early as 15 min postvenipuncture. However, delaying processing by more than 30 min leads to a significant change in results.
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Randomized Controlled Trial Comparative Study
The reliability of point-of-care prothrombin time testing. A comparison of CoaguChek S and XS INR measurements with hospital laboratory monitoring.
The development of point-of-care (POC) testing devices enables patients to test their own international normalized ratio (INR) at home. However, previous studies have shown that when compared with clinical laboratory values, statistically significant differences may occur between the two methods of INR measurement. The aim of this study was to evaluate the accuracy of the CoaguChek S and XS POC meters relative to clinical laboratory measurements. ⋯ A Bland-Altman plot illustrated good agreement of INR values between 2.0 and 3.5 INR units but there was increasing disagreement as the INR rose above 3.5. Eighty-seven per cent of all dual measurements were within the recommended 0.5 INR units of each other. This study adds to the growing evidence that POC testing is a reliable and safe alternative to hospital laboratory monitoring but highlights the importance of external quality control when these devices are used for monitoring oral anticoagulation.
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Comparative Study
Comparability of the results of PT-INR with local MNPT and APTTR with MNAPTT on different coagulation analyzers in China.
The prothrombin time (PT), International normalized ratio (INR) and activated partial thromboplastin time (APTT) are the most used coagulation tests in China, where more than one type of automated coagulation analyzer is often used in the clinical laboratory. The PT-INR results of 109 samples were compared with local mean normal PT (MNPT) and APTT ratio (APTTR) with mean normal APTT (MNAPTT) on two different coagulation analyzers in the same laboratory. ⋯ Meanwhile, there was no significant difference (P = 0.865) for APTTR with MNAPTT compared with APTT (P = 0.002) between the ACL Futura and CA 510. In conclusion, these analyzers showed very poor agreement for both the PT and APTT, but the calculation of ratios significantly improved agreement.
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An absolute erythrocytosis is present when the red cell mass is raised and the haematocrit is elevated above prescribed limits. Causes of an absolute erythrocytosis can be primary where there is an intrinsic problem in the bone marrow and secondary where there an event outside the bone marrow driving erythropoiesis. This can further be divided into congenital and acquired causes. ⋯ Those who do not fulfil these criteria require further investigation depending on the clinical scenario and initial results. The erythropoietin level provides some guidance as to the direction in which to proceed and the order and extent of investigation necessary in an individual patient. It should thus be possible to make an accurate diagnosis in the majority of patients.
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Clinically latent myeloproliferative disorders (MPDs) are important causes of what would otherwise be considered idiopathic hepatic (HVT) or portal vein thrombosis (PVT). They may be difficult to diagnose initially because the peripheral blood count may be normal at the time of thrombosis. A strong association between an activating mutation of the gene encoding one of the Janus kinase family of tyrosine kinases (JAK2(V617F)) and the Philadelphia chromosome-negative MPDs has been identified. ⋯ Fourteen (74%) of the 19 patients were heterozygous for JAK2(V617F) but did not meet diagnostic criteria for a MPD at the time of presentation with thrombosis. Prolonged follow-up established the presence of an overt MPD in 13 of the 14 patients after a median duration of 38 months. We recommend testing for JAK2(V617F) in all patients with unexplained HVT or PVT, to identify latent MPDs and prevent potential complications.