Thesis (doctoral)--Bayerische Ludwig Maximilians Universität, Munich, 1933.

Thesis (doctoral)--Bayerische Ludwig Maximilians Universität, Munich, 1933.

Laboratory tests are a primary resource for diagnosing patient diseases. However, physicians often make decisions based on a single laboratory result and have a limited perspective of the role of commonly-measured parameters in enhancing the diagnostic process. By providing a dynamic patient profile, the diagnosis could be more accurate and timely, allowing physicians to anticipate changes in the recovery trajectory and intervene more effectively. The assessment and monitoring of the circulatory system is essential for patients in intensive care units (ICU). One component of this system is the platelet count, which is used in assessing blood clotting. However, platelet counts represent a dynamic equilibrium of many simultaneous processes, including altered capillary permeability, inflammatory cascades (sepsis), and the coagulation process. To characterize the value of dynamic changes in platelet count, analytical methods are applied to datasets of critically-ill patients in (1) a homogeneous population of ICU cardiac surgery patients and (2) a heterogeneous group of ICU patients with different conditions and several hospital admissions. The objective of this study was to develop a methodology to anticipate adverse events using metrics that capture dynamic changes of platelet counts in a homogeneous population, then redefine the methodology for a more heterogeneous and complex dataset. The methodology was extended to analyze other important physiological parameters of the circulatory system (i.e., calcium, albumin, anion gap, and total carbon dioxide). Finally, the methodology was applied to simultaneously analyze some parameters enhancing the predictive power of various models. This methodology assesses dynamic changes of clinical parameters for a heterogeneous population of ICU patients, defining rates of change determined by multiple point regression and by the simpler fixed time parameter value ratios at specific time intervals. Both metrics provide prognostic information, differentiating survivors from non-survivors and have demonstrated being more predictive than complex metrics and risk assessment scores with greater dimensionality. The goal was to determine a minimal set of biomarkers that would better assist care providers in assessing the risk of complications, allowing them alterations in the management of patients. These metrics should be simple and their implementation would be feasible in any environment and under uncertain conditions of the specific diagnosis and the onset of an acute event that causes a patient's admission to the ICU. The results provide evidence of the different behaviors of physiologic parameters during the recovery processes for survivors and non-survivors. These differences were observed during the first 8 to 10 days after a patient's admission to the ICU. The application of the presented methodology could enhance physicians' ability to diagnose more accurately, anticipate changes in recovery trajectories, and prescribe effective treatment, leading to more personalized care and reduced mortality rates.

<p>Platelets are the smallest cells in the blood. They are formed in the bone-marrow and are important for the blood coagulation. Platelet tranfusions are given to patients propyhlactically before an operation but also in therapeutical purpose in connection with bleeding. It’s importent that the quality controls of the platelet concentrates are reliable.</p><p>ADVIA®60 (Bayer HealthCare) is a fully automated cell counter which uses impedance principle to count platelets in blood samples. The purpose of the study was to evaluate this new instrument for use in the blood bank of Akademiska Sjukhuset in Uppsala. The instrument was bought to be used for quality control of platelet concentrates. 30 samples from platelet concentrates, from both apheresis and from buffy coats, were analyzed 10 times each on ADVIA®60 and the coefficient of variation (CV) was calculated for each sample. CV variated from 0,8 % to 2,9 % which is good considering that according to Bayer HealthCare the CV should be < 5 % for thrombocytes on ADVIA®60. The instrument was newly calibrated when the study was performed. Platelet count can also be performed by immunological or optical principles.</p>

Platelets are the smallest cells in the blood. They are formed in the bone-marrow and are important for the blood coagulation. Platelet tranfusions are given to patients propyhlactically before an operation but also in therapeutical purpose in connection with bleeding. It’s importent that the quality controls of the platelet concentrates are reliable. ADVIA®60 (Bayer HealthCare) is a fully automated cell counter which uses impedance principle to count platelets in blood samples. The purpose of the study was to evaluate this new instrument for use in the blood bank of Akademiska Sjukhuset in Uppsala. The instrument was bought to be used for quality control of platelet concentrates. 30 samples from platelet concentrates, from both apheresis and from buffy coats, were analyzed 10 times each on ADVIA®60 and the coefficient of variation (CV) was calculated for each sample. CV variated from 0,8 % to 2,9 % which is good considering that according to Bayer HealthCare the CV should be &lt; 5 % for thrombocytes on ADVIA®60. The instrument was newly calibrated when the study was performed. Platelet count can also be performed by immunological or optical principles.

A contagem de plaquetas é um exame de rotina utilizado no auxilío do diagnóstico de diversos distúrbios hemostáticos, além de ser usada no monitoramento de pacientes, portanto existe a necessidade de obter parâmetros fidedignos para assegurar a existência de plaquetopenia ou plaquetose e alterações morfológicas destas células. A comum ocorrência de agregação plaquetária “in vitro” dificulta a análises destes parâmetros, evento devido ao uso incorreto da metodologia de coleta, armazenamento inadequado da amostra, assim como o uso incorreto do anticoagulante. O diagnóstico errôneo de plaquetopenia ou plaquetose pode ter como consequência o direcionamento terapêutico inadequado do paciente. O objetivo deste estudo foi comparar quantitativa e qualitativamente os parâmetros plaquetários em amostras com diferentes anticoagulantes, e diferentes tempo e temperatura de armazenagem. Além disso, foram também objetivos averiguar a diferença entre os métodos de contagem de plaquetas (automático, manual e estimado em lâmina), e a correlação entre o volume plaquetário médio (MPV) e a porcentagem de macroplaquetas, assim como definir um intervalo de referência para a porcentagem de macroplaquetas em uma população de cães sadios. Amostras de sangue foram coletadas através do sistema a vácuo em tubos de EDTA K2 e citrato de sódio 3,2% de 54 cães clinicamente saudáveis. As amostras foram separadas em duas alíquotas e posteriormente armazenadas em pares, um par a temperatura ambiente (25°C) e outro a 4°C por até 6 horas após coleta. Cada alíquota foi avaliada em três momentos diferentes, nos quais as contagens plaquetárias, o MPV, e o escore de agregação foram realizados. A porcentagem de macroplaquetas foi feita apenas nas amostras de EDTA armazenadas a 25°C, no tempo zero após a coleta. Foi observada uma diminuição significativa nas contagens plaquetárias com o passar do tempo e em amostras sob refrigeração, e uma tendência ao aumento dos valores de MPV. As contagens realizadas em amostras de EDTA foram mais elevadas do que aquelas em citrato, e não houve correlação entre o volume de plaquetário médio e a porcentagem de macroplaquetas e, além de que a freqüência de aglomeração foi maior em amostras citratadas armazenadas a 4°C. / The platelet count is a routine examination used in the diagnosis of bleeding disorders and patient monitoring. Therefore, reliable parameters are needed to ensure the existence of thrombocytopenia or thrombocytosis and morphological changes of these cells. The common occurrence of platelet aggregation difficult the analysis of these parameters, this often occurs due to incorrect venipuncture methodology, improper storage of the sample, as well as the incorrect use of anticoagulants. The misdiagnosis of thrombocytopenia or thrombocytosis may result in inappropriate treatment guidance. The aim of this study was to compare the quantitative and qualitative platelet parameters in samples with different anticoagulants, times and temperatures. Additional objectives were to, ascertain the difference between platelet count methods (automatic, manual and estimated) and to verify a possible correlation between the mean platelet volume (MPV) and macroplatelets percentage, as well as to define a reference range for macroplatelets percentage in a healthy population of dogs. Blood was collected from 54 clinically healthy dogs via vacuum system into EDTA K2 and sodium citrate 3.2% tubes. The samples were separated into two aliquots and then stored in pairs, one pair at room temperature (25°C) and another at 4°C for up to 6 hours post sampling. Each sample was evaluated at three different times, in which platelet counts, MPV, and clumping scores were performed. The macroplatelets percentage was done only in EDTA samples stored at 25°C, at zero hour post sampling. The authors observed a statistically significant decrease in platelet counts over time and in refrigerated samples, and a tendency to increased values of MPV. Counts performed in EDTA samples were higher than those in citrate, and there was no correlation between the mean platelet volume and macroplatelets percentage; and besides the frequency of clumping was higher in citrated samples stored at 4°C.

A contagem de plaquetas é um exame de rotina utilizado no auxilío do diagnóstico de diversos distúrbios hemostáticos, além de ser usada no monitoramento de pacientes, portanto existe a necessidade de obter parâmetros fidedignos para assegurar a existência de plaquetopenia ou plaquetose e alterações morfológicas destas células. A comum ocorrência de agregação plaquetária “in vitro” dificulta a análises destes parâmetros, evento devido ao uso incorreto da metodologia de coleta, armazenamento inadequado da amostra, assim como o uso incorreto do anticoagulante. O diagnóstico errôneo de plaquetopenia ou plaquetose pode ter como consequência o direcionamento terapêutico inadequado do paciente. O objetivo deste estudo foi comparar quantitativa e qualitativamente os parâmetros plaquetários em amostras com diferentes anticoagulantes, e diferentes tempo e temperatura de armazenagem. Além disso, foram também objetivos averiguar a diferença entre os métodos de contagem de plaquetas (automático, manual e estimado em lâmina), e a correlação entre o volume plaquetário médio (MPV) e a porcentagem de macroplaquetas, assim como definir um intervalo de referência para a porcentagem de macroplaquetas em uma população de cães sadios. Amostras de sangue foram coletadas através do sistema a vácuo em tubos de EDTA K2 e citrato de sódio 3,2% de 54 cães clinicamente saudáveis. As amostras foram separadas em duas alíquotas e posteriormente armazenadas em pares, um par a temperatura ambiente (25°C) e outro a 4°C por até 6 horas após coleta. Cada alíquota foi avaliada em três momentos diferentes, nos quais as contagens plaquetárias, o MPV, e o escore de agregação foram realizados. A porcentagem de macroplaquetas foi feita apenas nas amostras de EDTA armazenadas a 25°C, no tempo zero após a coleta. Foi observada uma diminuição significativa nas contagens plaquetárias com o passar do tempo e em amostras sob refrigeração, e uma tendência ao aumento dos valores de MPV. As contagens realizadas em amostras de EDTA foram mais elevadas do que aquelas em citrato, e não houve correlação entre o volume de plaquetário médio e a porcentagem de macroplaquetas e, além de que a freqüência de aglomeração foi maior em amostras citratadas armazenadas a 4°C. / The platelet count is a routine examination used in the diagnosis of bleeding disorders and patient monitoring. Therefore, reliable parameters are needed to ensure the existence of thrombocytopenia or thrombocytosis and morphological changes of these cells. The common occurrence of platelet aggregation difficult the analysis of these parameters, this often occurs due to incorrect venipuncture methodology, improper storage of the sample, as well as the incorrect use of anticoagulants. The misdiagnosis of thrombocytopenia or thrombocytosis may result in inappropriate treatment guidance. The aim of this study was to compare the quantitative and qualitative platelet parameters in samples with different anticoagulants, times and temperatures. Additional objectives were to, ascertain the difference between platelet count methods (automatic, manual and estimated) and to verify a possible correlation between the mean platelet volume (MPV) and macroplatelets percentage, as well as to define a reference range for macroplatelets percentage in a healthy population of dogs. Blood was collected from 54 clinically healthy dogs via vacuum system into EDTA K2 and sodium citrate 3.2% tubes. The samples were separated into two aliquots and then stored in pairs, one pair at room temperature (25°C) and another at 4°C for up to 6 hours post sampling. Each sample was evaluated at three different times, in which platelet counts, MPV, and clumping scores were performed. The macroplatelets percentage was done only in EDTA samples stored at 25°C, at zero hour post sampling. The authors observed a statistically significant decrease in platelet counts over time and in refrigerated samples, and a tendency to increased values of MPV. Counts performed in EDTA samples were higher than those in citrate, and there was no correlation between the mean platelet volume and macroplatelets percentage; and besides the frequency of clumping was higher in citrated samples stored at 4°C.

A contagem de plaquetas é um exame de rotina utilizado no auxilío do diagnóstico de diversos distúrbios hemostáticos, além de ser usada no monitoramento de pacientes, portanto existe a necessidade de obter parâmetros fidedignos para assegurar a existência de plaquetopenia ou plaquetose e alterações morfológicas destas células. A comum ocorrência de agregação plaquetária “in vitro” dificulta a análises destes parâmetros, evento devido ao uso incorreto da metodologia de coleta, armazenamento inadequado da amostra, assim como o uso incorreto do anticoagulante. O diagnóstico errôneo de plaquetopenia ou plaquetose pode ter como consequência o direcionamento terapêutico inadequado do paciente. O objetivo deste estudo foi comparar quantitativa e qualitativamente os parâmetros plaquetários em amostras com diferentes anticoagulantes, e diferentes tempo e temperatura de armazenagem. Além disso, foram também objetivos averiguar a diferença entre os métodos de contagem de plaquetas (automático, manual e estimado em lâmina), e a correlação entre o volume plaquetário médio (MPV) e a porcentagem de macroplaquetas, assim como definir um intervalo de referência para a porcentagem de macroplaquetas em uma população de cães sadios. Amostras de sangue foram coletadas através do sistema a vácuo em tubos de EDTA K2 e citrato de sódio 3,2% de 54 cães clinicamente saudáveis. As amostras foram separadas em duas alíquotas e posteriormente armazenadas em pares, um par a temperatura ambiente (25°C) e outro a 4°C por até 6 horas após coleta. Cada alíquota foi avaliada em três momentos diferentes, nos quais as contagens plaquetárias, o MPV, e o escore de agregação foram realizados. A porcentagem de macroplaquetas foi feita apenas nas amostras de EDTA armazenadas a 25°C, no tempo zero após a coleta. Foi observada uma diminuição significativa nas contagens plaquetárias com o passar do tempo e em amostras sob refrigeração, e uma tendência ao aumento dos valores de MPV. As contagens realizadas em amostras de EDTA foram mais elevadas do que aquelas em citrato, e não houve correlação entre o volume de plaquetário médio e a porcentagem de macroplaquetas e, além de que a freqüência de aglomeração foi maior em amostras citratadas armazenadas a 4°C. / The platelet count is a routine examination used in the diagnosis of bleeding disorders and patient monitoring. Therefore, reliable parameters are needed to ensure the existence of thrombocytopenia or thrombocytosis and morphological changes of these cells. The common occurrence of platelet aggregation difficult the analysis of these parameters, this often occurs due to incorrect venipuncture methodology, improper storage of the sample, as well as the incorrect use of anticoagulants. The misdiagnosis of thrombocytopenia or thrombocytosis may result in inappropriate treatment guidance. The aim of this study was to compare the quantitative and qualitative platelet parameters in samples with different anticoagulants, times and temperatures. Additional objectives were to, ascertain the difference between platelet count methods (automatic, manual and estimated) and to verify a possible correlation between the mean platelet volume (MPV) and macroplatelets percentage, as well as to define a reference range for macroplatelets percentage in a healthy population of dogs. Blood was collected from 54 clinically healthy dogs via vacuum system into EDTA K2 and sodium citrate 3.2% tubes. The samples were separated into two aliquots and then stored in pairs, one pair at room temperature (25°C) and another at 4°C for up to 6 hours post sampling. Each sample was evaluated at three different times, in which platelet counts, MPV, and clumping scores were performed. The macroplatelets percentage was done only in EDTA samples stored at 25°C, at zero hour post sampling. The authors observed a statistically significant decrease in platelet counts over time and in refrigerated samples, and a tendency to increased values of MPV. Counts performed in EDTA samples were higher than those in citrate, and there was no correlation between the mean platelet volume and macroplatelets percentage; and besides the frequency of clumping was higher in citrated samples stored at 4°C.

No description available.

Heparin is an anticoagulant widely administered to patients undergoing major orthopedic or cardiac surgery. Though heparin is effective at preventing thrombosis, it is paradoxically associated with the development of heparin-induced thrombocytopenia (HIT). HIT is strongly associated with thrombotic complications and is an adverse drug reaction that occurs when heparin binds to the self-protein, platelet factor 4 (PF4) and forms immunogenic multimolecular complexes. As a result, anti-PF4/heparin antibodies are formed, which bind to these complexes, and can cross-linking Fc receptors on platelets and monocytes causing intense platelet activation, thrombocytopenia, and thrombosis. Patients who receive heparin frequently form antibodies against these PF4/heparin complexes; however, most of these antibodies do not cause HIT. Over-diagnosis of HIT is common due to the detection of clinically insignificant non-pathogenic anti-PF4/heparin antibodies. Current enzyme immunoassays (EIAs) cannot distinguish between pathogenic and non-pathogenic anti-PF4/heparin antibodies and will give a false positive result in the presence of the clinically insignificant non-pathogenic anti-PF4/heparin antibodies. Further functional testing is required to identify samples containing the pathogenic anti-PF4/heparin antibodies that will lead to HIT; however, these tests are not readily available in most centres, and delay timely diagnosis. There is little known about the differences between pathogenic and non-pathogenic HIT antibodies. The identification of antigenic determinations of pathogenic HIT antibodies binding to PF4 from this project will have direct implications for patient care. We will be able to accurately and rapidly identify “true” HIT patients from learning more about the pathogenic HIT antibody epitope. / Dissertation / Doctor of Science (PhD) / At least 30% of patients admitted into the hospital will be exposed to the anticoagulant, heparin. 1-3% of these patients develop heparin-induced thrombocytopenia (HIT): an adverse drug reaction. HIT is a major cause of morbidity and mortality in patients receiving heparin if not diagnosed and treated in a timely manner. HIT occurs when patients form antibodies against the platelet protein, platelet factor 4, in complex with heparin leading to an immune response. However, most heparin-exposed patients produce these antibodies but do not have HIT. Current rapid and available diagnostics tools cannot distinguish between antibodies that can or cannot cause the disease. To improve HIT diagnosis, we will identify the molecular differences between the antibodies that cause HIT and those that do not. From this, we can develop a new diagnostic assay that will be able to dictate whether the antibodies found in patients are specific for HIT.