Background: Hemorrhage continues to be a prominent contributor to obstetric morbidity and mortality around the world. A rapid coagulation test would be a significant improvement for the diagnosis of coagulopathy and the management of obstetric hemorrhage. Conventional tests are time consuming, and while viscoelastic tests provide rapid results, but they require training and manipulation of samples that prevent widespread adoption.  The Quantra® Hemostasis analyzer is a novel, rapid coagulation analyzer that utilizes ultrasound to induce resonance and measure clot stiffness over time.

Aims: We evaluated the sensitivity of the Quantra compared to conventional coagulation tests (CL) to varying levels of fibrinogen, platelets and clotting factors in blood samples from pregnant women.

Methods: Blood was collected from healthy pregnant subjects at term into citrated tubes. Each subject’s samples were pooled, and aliquots were analyzed or diluted and reconstituted with plasma from pregnant or non-pregnant women to mimic fluid resuscitation (Figure 1). Neat or reconstituted samples were run in parallel on the Quantra and CL. Data was analyzed using regression analysis to correlate the Quantra parameters against CL.

Schematic of blood dilutions, reconstitutions and data analysis for each subject

Results: Eighty-nine samples from 13 parturients at term were analyzed. Figure 2 provides the mean (SD) of key Quantra and CL parameters at term gestation. There was a very high linear correlation between Fibrinogen and CS (R=0.93, P<0.001), Fibrinogen and FCS (R=0.77, P<0.001), and Platelet and PCS (R=0.90).  FCS and CS strongly predicted a fibrinogen <200 mg/dL based on the area under the ROC curves of 0.931 (95% CI 0.881-0.980) and 0.943 (95% CI 0.868-1.0), respectively.  The optimal threshold for FCS to detect fibrinogen <200 mg/dL in this patient population was 2.45 hPa (95% CI 2.35-3.05).

Effects of dilution and reconstitution on Quantra and conventional coagulation test parameters

Conclusions: The Quantra is a user-friendly cartridge-based coagulation monitoring system that rapidly provides a measure of a patient’s coagulation status which correlates well with conventional fibrinogen and platelet measurements.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/novel-point-of-care-rapid-coagulation-analyzer-for-obstetrics-quantra-seer-sonorheometry/