Estimation of the levels of D-dimer by use of an alternative method based in the reaction time of fibrinogen/fibrin degradation products assay.

BACKGROUND: D-dimer and fibrinogen/fibrin degradation products (FDP) levels are elevated in thromboembolic disorders, and its assays are used in many laboratories for the investigation of these disorders. The aim of this study was to propose a cost saving alternative method for determination of D-dimer levels based in the reaction time of FDP assay. METHODS: D-dimer and FDP immunoassays were performed in 100 blood samples from subjects by use of Liatest D-dimer and Plasma FDP. The results of D-dimer obtained by the Liatest D-dimer were compared with the results obtained by the estimation method. RESULTS: A significant association between D-dimer levels and the reaction times necessary to occur agglutination in latex agglutination test for FDP was observed. A close agreement between D-dimer results obtained by the Liatest D-dimer and by the estimation method (D-dimer = 82829 FDPt(-0.8683)) was observed. CONCLUSIONS: The estimation method described in this study could be useful for clinical laboratories because it allows estimating the D-dimer levels before of the automated systems analysis, reducing costs associated to dilutions of plasma samples and reagents.

Lack of association between cardiac troponin T and D-dimer in the evaluation of myocardial damage.

Acute myocardial infarction (AMI) disrupts cardiac cell membranes, releasing intracellular cardiac proteins into the vascular system. Some of these proteins, including the cardiac troponin subunits T and I, have proven useful for diagnosing myocardial damage. Intracoronary thrombosis plays a key role in the pathogenesis of AMI, and the formation of an occlusive thrombus usually precedes the development of myocardial damage. To evaluate whether there is an association between the size of intracoronary thrombosis and myocardial damage, we analyzed D-dimer and cTnT levels in blood samples from patients suspected to have myocardial damage. We investigated 102 patients who were admitted to emergency service for suspected myocardial damage. D-dimer was assessed with the use of the immunoassay Liatest D-dimer, and cTnT levels were measured with an electrochemiluminescence immunoassay (Troponin T STAT). D-dimer levels were lower in patients with cTnT < 0.01 than in patients presenting cTnT > 0.01 ng/mL. We investigated the relationship between D-dimer and cTnT levels in the patients with cTnT > 0.01 ng/mL (0.40 +/- 0.10 ng/mL), and no significant agreement (r = 0.20, P > 0.05) was observed. The levels of D-dimer were not associated with the levels of cTnT in patients with cTnT > 0.01 ng/mL.

D-dimer and its relationship to fibrinogen/fibrin degradation products (FDPs) in disorders associated with activation of coagulation or fibrinolytic systems.

Levels of D-dimer and fibrinogen/fibrin degradation products (FDPs) are significantly elevated in patients with deep venous thrombosis, pulmonary embolism, disseminated intravascular coagulation, or other complications. The diagnosis of these disorders can be difficult, time-consuming, and expensive. Assays for the detection of FDPs and D-dimer are used in many laboratories to investigate these disorders. The aim of this study was to compare plasma D-dimer levels obtained by the immuno-turdimetric method (Liatest D-Dimer Diagnostica Stago, Asnières, France) with plasma FDPs were measured by latex agglutination to investigate the relationship between these parameters. These immunoassays were tested in 144 blood samples from patients with suspected disorders associated with activation of coagulation or fibrinolytic systems. D-dimer and FDPs assays were performed in plasma samples by the use of Liatest D-dimer and plasma FDPs (Diagnostica Stago), respectively. Patients were divided into four groups according to plasma D-dimer levels. In group 1, 47.4% had negative FDPs and 52.6% had positive FDPs. In group 2, 15.4% had negative FDPs and 84.6% had positive FDPs. In group 3, 10.3% had negative FDPs and 89.7% had positive FDPs. All of the patients in group 4 had positive FDPs. It was shown that plasma D-dimer levels measured by Liatest D-dimer have a relation to FDP levels measured by latex agglutination.

Análise comparativa das técnicas manual e automatizada (ADVIA tm 120) para contagem de reticulócitos / Comparative analysis of manual and automated (ADVIA tm 120) reticulocytes counting

Os reticulócitos são células de origem eritróide com resíduos de RNA, sendo esses evidenciados com a utilização de colorações supravitais. O número de reticulócitos no sangue periférico reflete a atividade eritropoética da medula óssea. Considerando a importância da implantação de uma contagem de reticulócitos mais rápida e precisa, este trabalho tem por objetivo avaliar a correlação entre as técnicas manual e automatizada (ADVIA TM 120, Bayer Diagnostics) para contagem de reticulócitos. O equipamento ADVIA TM 120 utiliza uma reação citoquímica para a diferenciação e contagem de reticulócitos. Foram utilizadas nesse estudo 64 amostras de sangue obtidas de diferentes pacientes. As contagens foram realizadas pelas técnicas manual e automatizada, sendo que elas variaram de 0,6 a 10 porcento. Ao analisar os resultados obtidos pelas duas técnicas, foi possível observar uma forte correlação (r=0,9778, p<0,001) entre ambas. A implantação da técnica automatizada tem contribuído com a rotina do Laboratório Central de Análises Clínicas - ISCMPA, fornecendo resultados mais precisos em um menor tempo. A contagem de reticulócitos realizada no ADVIA tm 120 apresentou excelente correlação com a contagem manual, sendo bem mais prática, rápida e precisa.