PB1396 - Validation of clinical reference ranges for viscoelastometric assessment of haemostasis (TEG® 6S) and standard laboratory tests in obstetric patients

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

EC

Emily A. Crossland, MSc

Specialist Biomedical Scientist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom

Co-Author(s)

DW

Danielle White

Senior Biomedical Scientist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
JB

James Bamber

Consultant
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
RT

Rhys Tassell

POCT Lead
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
MB

Martin Besser

Consultant Haematologist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
ES

Emily Symington

Consultant Haematologist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
MR

Mark Robinson

Consultant Haematologist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
William Thomas, MB BS

Consultant Haematologist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom
Stephen MacDonald, MPhil

Principal Clinical Scientist
Cambridge University Hospitals NHS Foundation Trust
Cambridge, England, United Kingdom

Background: To prevent excessive bleeding during delivery, pregnancy causes a hypercoagulable state by reducing natural anticoagulants and increasing procoagulant factors. Such changes are reflected in standard laboratory tests (SLTs). During emergent situations, SLTs often do not reflect the current haemostatic profile due to excessive turnaround time. The Thromboelastograph (TEG® 6S) is capable of assessing coagulation and fibrinolysis rapidly, within 20 minutes, favouring its use in urgent clinical situations including massive haemorrhage during delivery. Manufacturer, reference ranges are provided for all parameters.

Aims: Are reference ranges to represent haemostasis in late pregnancy, both for viscoelastometry and Standard Laboratory tests required and can they be applied to represent the haemostatic profile in a more clinically represntative manner?

Methods: This study was a prospective observational study involving the enrolment of 69 pregnant women near full term attending the elective C-Section clinic at The Rosie Hospital, Cambridge, UK between 8th of February 2021 and 28th of April 2021. All participants were recruited, with full informed consent. The aim of this study was to confirm coagulation changes in late pregnancy and determine pregnancy specific reference ranges for viscoelastic and SLTs using CLSI EP28-A3c.

Results: Although reference ranges of late pregnancy patients were within the reference ranges stated by the manufacturer, the distribution of results differed. All parameters demonstrated a hypercoagulable profile, close to the hypercoagulable extreme of the manufacturer ranges. This reduces the sensitivity of the manufacturer ranges for detecting deviations from baseline. Locally validated reference ranges improve sensitivity to detect risk of bleeding, reflected in abnormal viscoelastic parameters

Conclusion(s): The results observed confirmed the hypercoagulable state experienced during late pregnancy. These results provide additional evidence for the need for establishment of obstetric specific reference ranges on the TEG® 6s point of care analyser.