Peri-partum reference range for the point-of-care viscoelastic testing device Quantra® QStat in healthy pregnancy and...

The Quantra® QStat is a novel point-of-care viscoelastometric test based on sonorheometry technology. Reference ranges in obstetric settings have not yet been established. The QStat measures five parameters: clotting time (CT, seconds (s)), clotting stiffness (CS, hectopascals (hPA)), fibrinogen (FCS, hPA) and platelet contribution to clot stiffness (PCS, hPA), and clot stability to lysis (CSL, percentage (%)).

A prospective observational study was conducted in two French academic hospitals to determine the reference range in full-term healthy pregnant women. The QStat measurements were performed upon admission to the delivery room and thirty to sixty minutes after uncomplicated vaginal or caesarean delivery. The primary analysis involved defining reference intervals, expressed as the means, standard deviations, distributions, and dispersions. The secondary analysis compared values between pregnant and nonpregnant patients, between the prepartum and postpartum periods, and between vaginal and caesarean delivery methods.

Over one year, in 84 patients, the QStat parameter ranges were established for the end of pregnancy and immediate postpartum periods. The CT and FCS values differed between pregnant and nonpregnant women. No significant difference was found between the prepartum and postpartum values or between vaginal and caesarean delivery groups.

The QStat is a promising point-of-care viscoelastometric testing device that is now desirable for managing postpartum haemorrhage to enable haemostasic goal-oriented therapies. Similar to viscoelastometric testing in trauma and cardiac surgery, the QStat provides reliable measurements. Further research is needed to establish pathological reference values specific to the obstetric bleeding scenario.

ClinicalTrial.gov: NCT04753671.