Efficacy of sonorheometry point of the care device in determining low fibrinogen levels in pregnant blood: an invitro dilution and reconstitution study

Abstract

Quantra® Hemostasis Analyzer is a Point of the care device that uses ultrasound technology to assess clot formation. In this study, we establish how Quantra® system performs compared to conventional coagulation tests at low levels of fibrinogen in the blood obtained from pregnant women. 24 mL blood was obtained from each healthy parturient. Blood was analyzed for Quantra® variables (Q): Clot time (CT), Clot stiffness (CS), platelet contribution to CS (PCS), fibrinogen contribution to CS (FCS), and conventional coagulation (CL) tests: PT, aPTT, INR, Factor VIII and fibrinogen. 6 ml blood were centrifuged to obtain pregnant plasma. 30 mL of saline was added to 10 mL of blood to simulate crystalloid resuscitation (DB) and was evaluated for Q and CL. Fractions of pregnant plasma, or nonpregnant plasma (Blood Bank) was added to DB to obtain 15% and 30% clotting factor enriched samples. 4 ml of DB was added to 4 ml of original blood (1:1) to obtain the final sample (resus). Each of the samples were analyzed for Q and CL parameters. Regression analysis and Receiving Characteristics Curves were used to study the relationship between Quantra variables and CL tests. There were remarkably high linear correlations between Fibrinogen and CS (R = 0.93, P < 0.001), fibrinogen and FCS (R = 0.77, P < 0.001). An FCS value 2.45 (sensitivity of 79.2 and specificity of 97.3%), and CS value 10.85 hPa (sensitivity of 83% and specificity of 100%) predicted fibrinogen of 200 mg/dL. This study demonstrates a good correlation between Quantra® CS, FCS and serum fibrinogen. Clinical Trial Number: NCT04301193.