The effect of sepsis and its inflammatory response on mechanical clot characteristics: a prospective observational study

Purpose: Sepsis and its progression are known to have a major influence on the coagulation system. Current coagulation tests are of limited use when assessing coagulation in sepsis patients. This study aims to assess the potential for a new functional biomarker of clot microstructure, fractal dimension, to identify changes in the mechanical properties of clot microstructure across the sepsis spectrum (sepsis, severe sepsis and septic shock). Methods: A total of 100 patients that presented acutely to a large teaching hospital were included in this prospective observational study (50 sepsis, 20 severe sepsis and 30 septic shock) against a matched control of 44 healthy volunteers. Fractal analysis was performed, as well as standard markers of coagulation, and six plasma markers of inflammation. Results: Fractal dimension was significantly higher in the sepsis and severe sepsis groups than the healthy control (1.78 ± 0.07 and 1.80 ± 0.05 respectively vs 1.74 ± 0.03) (p < 0.001), indicating a significant increase in mechanical clot strength and elasticity consistent with a hypercoagulable state. Conversely, fractal dimension was significantly lower in septic shock (1.66 ± 0.10, p < 0.001), indicating a significant reduction in mechanical clot strength and functionality consistent with a hypocoagulable state. This corresponded with a significant increase in the inflammatory response. Conclusions: This study confirms that clot microstructure is significantly altered through the various stages of sepsis. Of particular importance was the marked change in clot development between severe sepsis and septic shock, which has not been previously reported

Pre-analytical issues in the haemostasis laboratory: guidance for the clinical laboratories

Ensuring quality has become a daily requirement in laboratories. In haemostasis, even more than in other disciplines of biology, quality is determined by a pre-analytical step that encompasses all procedures, starting with the formulation of the medical question, and includes patient preparation, sample collection, handling,transportation, processing, and storage until time of analysis. This step, based on a variety of manual activities, is the most vulnerable part of the total testing process and is a major component of the reliability and validity of results in haemostasis and constitutes the most important source of erroneous or un-interpretable results. Pre-analytical errors may occur throughout the testing process and arise from unsuitable, inappropriate or wrongly handled procedures. Problems may arise during the collection of blood specimens such as misidentification of the sample, use of inadequate devices or needles, incorrect order of draw, prolonged tourniquet placing, unsuccessful attempts to locate the vein, incorrect use of additive tubes, collection of unsuitable samples for quality or quantity, inappropriate mixing of a sample, etc. Some factors can alter the result of a sample constituent after collection during transportation, preparation and storage. Laboratory errors can often have serious adverse consequences. Lack of standardized procedures for sample collection accounts for most of the errors encountered within the total testing process. They can also have clinical consequences as well as a significant impact on patient care, especially those related to specialized tests as these are often considered as “diagnostic”. Controlling pre-analytical variables is critical since this has a direct influence on the quality of results and on their clinical reliability. The accurate standardization of the pre-analytical phase is of pivotal importance for achieving reliable results of coagulation tests and should reduce the side effects of the influence factors. This review is a summary of the most important recommendations regarding the importance of pre-analytical factors for coagulation testing and should be a tool to increase awareness about the importance of pre-analytical factors for coagulation testing