Objective: There has been little published work about the reference intervals of thromboelastography (TEG®) tests in pregnancy. Our aim was to establish the trimester-specific reference intervals of TEG tests for healthy pregnant women.
Methods: After excluding outliers, a total of 753 apparently healthy pregnant women aged from 19 to 44 years including 252 first trimester women, 340 second trimester women and 161 third trimester women were enrolled in our study. Non-fasting venous blood samples were collected. TEG tests were done on kaolin activated samples and processed on TEG 5000 Hemostasis Analyzer. Nonparametric 2.5th-97.5th percentile intervals were used to define the reference intervals.
Results: There were significant differences for TEG tests in pregnant women compared with non-pregnant women. The reference intervals for R, K, Angle, MA, Ly30 and CI were 4.1-10.4 min, 0.9-3.1 min, 53.6-75.9°, 46.1-69.8 mm, 0-10.7% and -5.5-2.5 respectively at first trimester; 3.9-9.7 min, 0.8-2.4 min, 56.7-78.0°, 49.8-72.1 mm, 0-9.7% and -3.7-2.9 at second trimester; 3.8-9.0 min, 0.8-2.5 min, 57.6-79.3°, 49.4-75.9 mm, 0-8.8% and -3.0-2.6 at third trimester.
Conclusions: We established trimester-specific reference intervals of TEG® tests for healthy pregnant women. It's critical to accurate assessment of global haemostatic status during pregnancy and in pregnancy complications.
Keywords: Haemostasis; Healthy; Pregnancy; Reference ranges; Thromboelastography.
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