Rapid-SF: A Rapid Whole-Blood Screen for Soluble Fibrin Monomer

Abstract

SummaryThrombosis accounts for a high proportion of disability and death in the West. Although soluble fibrin (SF) assays have been shown to be good predictors of thrombosis, current quantitative assays are too complex or lengthy to provide timely results, while simpler methods are qualitative and lack sensitivity. We here describe a rapid, new, protamine-based whole-blood screening method for SF which is quantitative and suitable for point-of-care use. Citrated whole blood is mixed with reagent under controlled conditions and the time until development of an SF precipitate is measured. Negative samples remain precipitate-free for 300 seconds. Strongly positive samples develop precipitate in as little as 10 seconds. SF times are mathematically converted to arbitrary SF units (SFU). This Rapid-SF test provides a simple and reliable means of detecting the presence of SF, and is well-suited for whole-blood rapid screening in the emergency department, operating room or clinic.

Mechanism of hypocoagulability in proton-irradiated ferrets

“…Blood samples were incubated at 37 ° Celsius (C) for 1 h with rotation to ensure proper mixing. Three drops of blood were discarded and then three drops of blood were added to a borosilicate tube containing protamine sulfate (Elkins-Sinn, Inc., Cherry Hill, NJ, USA) that was freshly prepared, as previously described by Hay and Bull (2002). The tube was gently mixed, placed in an oscillator and the time until precipitation was recorded.…”

“…The tube was gently mixed, placed in an oscillator and the time until precipitation was recorded. Results were reported as soluble fibrin units (SFU), which were calculated as described by Hay and Bull (2002).…”

“…Soluble fibrin is found in blood after the activation of the coagulation cascade. A rapid soluble fibrin assay (rapid-SF) was developed at the Loma Linda University Medical Center (LLUMC) for whole blood to aid in early detection of disseminated intravascular coagulation (DIC) in emergency room, operating room, or transplant patients; implementation of the rapid-SF assay has been employed over the last decade at LLUMC (Hay and Bull 2002). This assay system allowed us to measure the activation of the coagulation cascade in irradiated or sham-irradiated ferrets in response to proton radiation exposures.…”

Biological effects of space radiation and development of effective countermeasures

“…To test this hypothesis, a separate experiment was performed with 12 to 15 week old de-scented female ferrets irradiated with 1 Gy of 110-MeV protons at a dose rate of 0.5 Gy/hour, and the results indicate that the radiation exposure resulted in coagulation cascade activation, which was indicated by increases in soluble fibrin concentration in the blood and fibrin clots in blood vessels of livers, lungs and kidneys from irradiated ferrets (208). The soluble fibrin concentration was determined using a rapid soluble fibrin assay that was previously developed and implemented at the Loma Linda University Medical Center to aid in early detection of DIC in emergency room, operating room, or transplant patients (209). In addition to the activated coagulation cascade, PT and aPTT were also increased after irradiation, which is indicative of the involvement of the extrinsic/intrinsic coagulation pathways.…”

Is Disseminated Intravascular Coagulation the Major Cause of Mortality from Radiation at Relatively Low Whole Body Doses?

“…Our current studies in ferrets have shown that SPE proton radiation exposure at 1 Gy leads to increased bleeding times, concentrations of soluble fibrin in blood, and fibrin clotting in the livers, lungs and kidneys of irradiated ferrets within 24 h postirradiation (3, 4). The measurement of soluble fibrin in the blood is a marker for DIC in the clinic (5). DIC occurs when the clotting cascade is activated and is characterized by simultaneous bleeding and clotting.…”