Reference values for kaolin-activated thromboelastography in volunteers of Anhui Province in China

Establishment of Normal Range for Thromboelastography in Healthy Middle-Aged and Elderly People of Weihai in China

TEG can monitor the dynamic changes of blood clot formation and lysis by activating the coagulation system of a small sample of whole blood in vitro. The parameters can reflect the level of coagulation factors, the function of fibrinogen and platelet, and the presence or absence of hyperfibrinolysis. At present, the normal reference range of the parameters of TEG is mainly based on the reference values established by the Western population. Due to the differences in the distribution of ethnic groups, many countries have established their reference ranges for healthy populations. In China, some scholars have tried to establish the corresponding TEG reference range according to the characteristics of the population in different regions. This study tried to establish the reference range for thromboelastography in healthy middle-aged and elderly people of Weihai in China and compare it with the reference range provided by the manufacturer. The fasting venous blood of 454 healthy middle-aged and elderly people was collected, including 239 males and 215 females. The thromboelastography TEG-5000 was used to measure the reaction time (R), coagulation formation time (K), coagulation angle (Angle), and maximum amplitude (MA). The reference range of TEG parameters of middle-aged and elderly healthy males was R: 4.38–8.27 min, K: 1.44–2.82 min, Angle: 48.53–72.17 deg, and MA: 51.95–72.02 mm; respectively, in the females, the normal value was R: 3.43–7.40 min, K: 1.07–2.53 min, Angle: 48.22–77.22 deg, and MA: 53.10–74.58 mm; The difference of R, K, Angle, and MA between the male group and the female group was statistically significant (P < 0.05); In this study, if we use the reference range established by the manufacturer, the R specificity for males was 91.6%, K specificity was 98.7%, Angle specificity was 85.8%, and MA specificity was 93.7%; the range for females was 68.4%, 99.5%, 75.8%, and 87.4%, respectively. There are statistically significant differences between R, K, Angle, and MA in middle-aged and elderly healthy women and men. It is necessary to establish a TEG reference range for healthy females and males.

A multicenter reference interval study of thromboelastography in the Chinese adult population

BACKGROUND

Imprecise reference intervals (RIs) adversely impact the determination of the need for blood transfusion and clinical diagnosis and treatment of coagulopathy. However, there are few RI studies of thromboelastography (TEG) based on a standard protocol. The present multicenter study aimed to establish RIs for the adult Chinese population.

METHODS

Healthy participants were recruited from 6 medical centers by non-probability sampling. Blood samples were subjected to laboratory TEG analysis. The Ichihara method, 2-level nested analysis of variance (ANOVA) (2N-ANOVA), and the latent abnormal values exclusion (LAVE) were used to define the RIs following recommendations of the Clinical and Laboratory Standards Institute and International Federation of Clinical Chemistry and Laboratory Medicine, Committee on Reference Intervals and Decision Limits. Multiple regression analysis was performed to explore sources of variation.

RESULTS

A total of 507 healthy participants were enrolled into the study cohort. Twenty-five individuals with potential coagulopathy were secondarily excluded by LAVE. Smoking was related to reaction time, α angle, and coagulation index in the TEG test (P < 0.05). 2N-ANOVA revealed that the RIs of all 5 test items of TEG needed to be partitioned by age and sex. Finally, TEG RIs were derived both parametrically and nonparametrically for males or females and different age Groups, respectively.

CONCLUSIONS

TEG RIs were established for the adult Chinese population using up-to-date methodology. The results will provide a useful and essential comparator for patients in the assessment of coagulation state, goal-directed blood transfusion therapy, and monitoring of the pharmacodynamic effects of anticoagulant drugs.

Thromboelastography and rotational thromboelastometry for the surgical intensivist: A narrative review

BACKGROUND

Viscoelastic tests (VETs), specifically thromboelastography (TEG) and rotational thromboelastometry (ROTEM), are gaining popularity in the management of critically ill surgical patients with hemorrhage or thrombosis due to their comprehensive characterization of the coagulation process and point-of-care availability in comparison to conventional coagulation tests (CCTs). We review current evidence for VET use in patients in the surgical intensive care unit (SICU).

METHODS

We searched PUBMED, EMBASE and the Cochrane Library through May 30, 2018 for articles that evaluated the use of VETs in patient populations and clinical scenarios germane to the surgical intensivist. Individual articles were critically evaluated for relevance and appropriate methodology using a structured technique. Information on patient characteristics, timing and methods of CCTs/VETs, and outcomes was collected and summarized in narrative form.

RESULTS

Of 2,589 identified articles, 36 were included. Five (14%) were interventional studies and 31 (86%) were observational. Twenty-five (69%) evaluated TEG, 11 (31%) ROTEM and 18 (50%) CCTs. Investigated outcomes included quantitative blood loss (13 (36%)), blood product transfusion (9 (25%)), thromboembolic events (9 (25%)) and mortality (6 (17%)). We identified 12 clinical scenarios with sufficient available evidence, much of which was of limited quantity and poor methodological quality. Nonetheless, research supports the use of VETs for guiding early blood product administration in severe traumatic hemorrhage and for the prediction of abstract excess bleeding following routine cardiac surgery. In contrast, evidence suggests VET-based heparin dosing strategies for venous thromboembolism prophylaxis are not superior to standard dosing in SICU patients.

CONCLUSION

While VETs have the potential to impact the care of critically ill surgical patients in many ways, current evidence for their use is limited, mainly because of poor methodological quality of most available studies. Further high-quality research, including several ongoing randomized controlled trials, is needed to elucidate the role of TEG/ROTEM in the SICU population.

LEVEL OF EVIDENCE

Systematic review, level IV.

Establishment of thromboelastography reference intervals by indirect method and relevant factor analyses

Thromboelastography (TEG) as a global coagulation test has been continuously developed for many decades in either research or clinical practice. The versatility of TEG test leads to difficulty in standardization and result interpretation. Reference intervals (RIs) of TEG may be one of the most controversial factors that influence its wide applications. RIs establishment with the traditional method is time‐consuming and laborious as well as beyond general laboratory capability. Indirect method using stored data and with statistical calculation and small cost is emerging as an alternative approach for RIs determination. Gender, age, or both affect RIs and must be taken into account before RIs estimation. The present study retrospectively collected a total of 930 TEG results as subjects and established RIs with indirect method for Kaolin‐activated TEG, including the parameters of R, K, αAngle, MA, and CI. Furthermore, gender, age, and gender‐dependent age subsets analyses were performed to determine their effects on RIs of TEG. In this study, we found that TEG parameters showed more hypercoagulability in female than male, most of the measured TEG variables were significantly associated with aging, but only in male statistical significance was found among different age stratification and 60‐year‐old could be considered as cutting point to differentiate coagulation ability in male. In addition, RIs of TEG were estimated by indirect method suitably and verified to be valid in our study. Finally, the RIs of TEG by indirect method were basically significantly different to the RIs recommended by manufacturer, but the consistent percentage is relatively high in the most of measured parameters. In conclusion, it is suggestive that the indirect method for RIs establishment is feasible, but relevant factors, such as gender and age, specifically gender‐dependent age effect, should be considered before RIs determinations.

Establishment of the Normal Reference Range of Thrombelastogram among the Healthy Population and Pregnants in China

BACKGROUND

We aimed to establish the reference range of thrombelastogram (TEG) for Chinese healthy volunteers and pregnant women and analyze the influence factors.

METHODS

Blood samples were collected from healthy volunteers and pregnant women at five tertiary hospitals (the Third Xiangya Hospital of Central South University, the Second Xiangya Hospital of Central South University, Hunan Provincial People's Hospital, Hunan Cancer Hospital and Changsha Central Hospital) in 2016. The effects of age, gender, blood type, and full-term pregnancy on the reference range of normal TEG for healthy volunteers and pregnant women were studied. The specificity of TEG in detecting coagulation disorder.

RESULTS

For healthy volunteers, the normal ranges of TEG parameters were as follows: R, 4.3-9.3 min; K, 1.2-3.2 min; α, 50.2-71.2°; MA, 54.1-71.3 mm; LY30: 0%-2.2%; CI, -3.8-2.4. At least one parameter exceeded the normal range specified by the manufacturer in 20.3% of the healthy volunteers; about 7.6% healthy volunteers were diagnosed as coagulation disorder by the above standards; the specificity of detection was 79.7%. There were significant differences in R, K, α, MA and CI between males and females (P<0.01). For pregnant women, the normal ranges of TEG were as follows: R, 3.9-7.5 min; K, 1.0-2.4 min; α, 57.6-74.9°; MA, 55.7-75.7 mm; LY30, 0%-0.56%; CI, -0.97-3.6. Pregnant women having O blood group had a dramatically prolonged R. Full-term pregnancy had no significant impact on TEG results.

CONCLUSION

Compared with pregnant women having non-O blood group, those having O blood group had a dramatically prolonged R and showed greater tendency to hemorrhage during and after parturition.

Reference values for kaolin-activated thromboelastography in volunteers of Anhui Province in China

BACKGROUND

The assessment of the coagulation status using thromboelastography (TEG) in Chinese population has less been reported. This study aimed to establish reliable reference values for kaolin-activated TEG in Chinese volunteers.

METHODS

A total of 1681 Chinese adult individuals were recruited for this study. The reference individuals were stratified by gender and age, and the TEG values were measured on the basis of strict quality control. The 95% reference values were determined using nonparametric statistical methods.

RESULTS

The sex-related 95% reference values were reaction time (R):4.2-8.7 minutes; clotting time (K): 1.2-3.2 minutes; alpha angle (α): 47.0-72.3 degree; maximum amplitude (MA): 49.1-70.5 mm for males, and R: 3.7-9.0 minutes; K: 1.0-3.2 minutes; α: 48.4-74.4 degree; MA: 46.8-72.4 mm for females. Also, the TEG parameters indicated a relatively more hypercoagulable profile in both female and elder groups.

CONCLUSIONS

This study established the reference values for kaolin-activated TEG in the target Chinese population, which might provide a reference for both clinical and laboratory studies.