In vitro hemocompatibility testing: The importance of fresh blood

Abstract

The use of unactivated blood for hemocompatibility testing is essential to obtain reliable results. Here, the authors study the influence of heparinized whole blood storage time and temperature on blood activation and evaluate the importance of initiating hemocompatibility tests within 4 h of blood collection. Blood from healthy volunteers was collected and analyzed with minimal delay, after 30 min and after 60 min of storage at room temperature, 30 or 37 °C. In addition, blood was analyzed after 1, 2, or 4 h of storage at room temperature. Platelet count, mean platelet volume, platelet binding capacity to collagen and thromboxane B2 were measured to assess platelet function, complement complex C5b-9 and elastase were measured to assess activation of the inflammatory response system, and thrombin-antithrombin III was measured to assess activation of the coagulation system. Furthermore, free hemoglobin was measured in platelet poor plasma as an indicator for red blood cell damage. The authors found that storage at 30 °C significantly increased platelet and coagulation activity after 60 min and storage at 37 °C significantly increased platelet, coagulation, and white blood cell activity after 60 min. Storage at room temperature significantly decreased platelet binding to collagen after 4 h and increased platelet activity after 1 h onward and white blood cell activity after 4 h. Their results show that short-term storage of heparinized whole blood significantly influences biomarkers over time, especially at 30 and 37 °C compared to room temperature. However, blood stored at room temperature for 4 h is also affected. In particular, platelet function and white blood cell activity are significantly influenced after 4 h of stationary storage at room temperature; therefore, the authors propose that hemocompatibility tests should be initiated well within 4 h of blood collection, preferably within 2 h.

In vitro blood flow model with physiological wall shear stress for hemocompatibility testing—An example of coronary stent testing

“…In this way, up to 40 test loops can be filled within 20 min from blood withdrawal, complying with the recommendation of using fresh blood for in vitro testing. 18 Choosing tubing with a different diameter for the test loop enables the assessment of medical devices with varying diameters. The limited volume of blood necessary for filling a single test loop enables the use of paired test samples, i.e., using blood from the same donor for test and control samples.…”

Capillary flow-driven microfluidic device with wettability gradient and sedimentation effects for blood plasma separation

“…It is also an active indicator of various pathological disorders1. Analysis of the cells in blood, the occurrence of viral or bacterial components and the imbalances in the composition of blood can be used for the detection of diseases and organ malfunctioning2.…”

The optimal incubation time for in vitro hemocompatibility testing: Assessment using polymer reference materials under pulsatile flow with physiological wall shear stress conditions

“…The lack of standardized methods for hemocompatibility testing constitutes a major problem for the preclinical evaluation of blood contacting medical devices. Direct contact of biomaterials with blood results in the activation of platelets, white blood cells, the coagulation cascade, the complement system, and can lead to hemolysis . Activation of these biological systems can occur throughout the entire cardiovascular system and can result in the formation of thrombi and (micro)embolisms which in turn can lead to life‐threatening conditions.…”