Estabilidade pré-analítica de parâmetros de coagulação em plasma citratado armazenado à temperatura ambiente
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2022-03-04
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O sistema hemostático tem extrema importância pois é um processo fisiológico que tem como objetivo proteger o sistema vascular, permitindo que caso ocorra lesão dos vasos, todos os tecidos consigam ser reparados. Outra função do sistema hemostático é manter o sangue no seu estado fluido dentro dos vasos sanguíneos, sem ocorrerem casos de trombose ou hemorragia. A hemóstase está dividida em vascular, primária e secundária. Para a avaliação do sistema hemostático são utilizados vários testes laboratoriais. Estes permitem avaliar a taxa de formação do coágulo sanguíneo a partir do momento de ativação da cascata de coagulação. O tempo de protrombina (PT), o tempo de tromboplastina parcial ativada (aPTT), o fibrinogénio e os D-dímeros são alguns deles. Os testes mencionados são também utilizados na prática Médico-Veterinária. O tempo de protrombina (PT) avalia a via comum e a via extrínseca. O tempo de tromboplastina parcial ativada (aPTT) permite avaliar a via intrínseca da cascata de coagulação. O fibrinogénio é uma proteína que se encontra envolvida na formação de coágulos sanguíneos. Por fim, os D-dímeros são os produtos finais da degradação da fibrina. Alguns destes testes são realizados no LPC do HVUTAD, tais como, o PT e o aPTT. No entanto os restantes são enviados para o exterior. Durante o transporte para os laboratórios as amostras estão sujeitas a mudanças de temperatura que depois podem interferir com a veracidade dos resultados. Para contornar estes efeitos foi estudado a estabilidade das amostras quando armazenadas à temperatura ambiente. Foram utilizadas amostras de sangue de 5 animais saudáveis consultados no Hospital Veterinário da UTAD. Algumas destas amostras foram centrifugadas após chegarem ao laboratório enquanto outras foram centrifugadas apenas no momento da análise para podermos estudar se a separação dos componentes afeta ou não a estabilidade das amostras. Essas amostras foram analisadas no aparelho de coagulação STart 4 ®onde são realizados os testes de PT, aPTT, Fibrinogénio e D-dímeros. Depois de realizar a estatística descritiva foi possível verificar que, no meu estudo, as amostras se mantêm estáveis quando armazenadas à temperatura ambiente até às 48 horas para alguns dos testes de coagulação.
The hemostatic system is extremely important because it is a physiological process that aims to protect the vascular system by allowing tissue reparation in case of vessel damage. Another function of the hemostatic system is to keep the blood in its fluid state inside the blood vessels, without the occurrence of thrombosis or bleeding. Hemostasis is divided into vascular, primary and secondary. In order to evaluate the hemostatic system, several laboratory tests are used that allow us to examine the rate of blood clot formation after the activation of the coagulation cascade. Prothrombin Time (PT), Activated Partial Thromboplastin Time (aPTT), fibrinogen and D-dimers are some of these tests and are also used in medical and veterinary practice. Prothrombin Time (PT) assesses the common pathway and the extrinsic pathway, the longest in the coagulation cascade. Activated Partial Thromboplastin Time (aPTT) allows us to assess the intrinsic pathway of the coagulation cascade. Fibrinogen is a protein that is involved in the formation of blood clots. Lastly, D-Dimers detect fibrin degradation products. Some of these tests are performed at the Clinical Pathology Lab of UTAD's Veterinary Hospital, such as PT and aPTT. However, the rest are sent to other labs. During transportation to the laboratories, the samples are subject to temperature changes that can later interfere with the veracity of the results. To circumvent these effects, the stability of the samples was studied when they were stored at room temperature. Blood samples from 5 healthy patients from the UTAD's Veterinary Hospital were used. Some of these samples were centrifuged after reaching the laboratory whilst others were centrifuged only at the time of analysis in order to study whether component separations affect the stability of the samples or not. These samples were analyzed in the Stago ® coagulation apparatus. After performing descriptive statistics, it was possible to verify that, in my study, the samples remain stable when stored at room temperature for up to 48 hours for some of the coagulation tests.
The hemostatic system is extremely important because it is a physiological process that aims to protect the vascular system by allowing tissue reparation in case of vessel damage. Another function of the hemostatic system is to keep the blood in its fluid state inside the blood vessels, without the occurrence of thrombosis or bleeding. Hemostasis is divided into vascular, primary and secondary. In order to evaluate the hemostatic system, several laboratory tests are used that allow us to examine the rate of blood clot formation after the activation of the coagulation cascade. Prothrombin Time (PT), Activated Partial Thromboplastin Time (aPTT), fibrinogen and D-dimers are some of these tests and are also used in medical and veterinary practice. Prothrombin Time (PT) assesses the common pathway and the extrinsic pathway, the longest in the coagulation cascade. Activated Partial Thromboplastin Time (aPTT) allows us to assess the intrinsic pathway of the coagulation cascade. Fibrinogen is a protein that is involved in the formation of blood clots. Lastly, D-Dimers detect fibrin degradation products. Some of these tests are performed at the Clinical Pathology Lab of UTAD's Veterinary Hospital, such as PT and aPTT. However, the rest are sent to other labs. During transportation to the laboratories, the samples are subject to temperature changes that can later interfere with the veracity of the results. To circumvent these effects, the stability of the samples was studied when they were stored at room temperature. Blood samples from 5 healthy patients from the UTAD's Veterinary Hospital were used. Some of these samples were centrifuged after reaching the laboratory whilst others were centrifuged only at the time of analysis in order to study whether component separations affect the stability of the samples or not. These samples were analyzed in the Stago ® coagulation apparatus. After performing descriptive statistics, it was possible to verify that, in my study, the samples remain stable when stored at room temperature for up to 48 hours for some of the coagulation tests.
Descrição
Dissertação do Mestrado em Biologia Clínica Laboratorial
Palavras-chave
Start4 , Hemóstase