An overview of the potential sources of diagnostic errors in (classic) thromboelastography curve interpretation and preventive measures

Kaolin activation of recalcified citrated whole blood in a point-of-care viscoelastic coagulation test

The viscoelastic coagulation monitor (VCM) is described as a point-of-care analyzer relying on activation of fresh whole blood (FWB) via contact between 2 glass plates. Kaolin is used as an activator in thromboelastography to reduce variability and shorten clotting times. The goal of this study was to compare VCM results from kaolin-activated, recalcified citrated samples with that from FWB. The VCM testing was performed using FWB and kaolin-activated, recalcified citrated samples. The VCM results were recorded for clot time (CT; seconds), clot formation time (CFT; seconds), alpha (degree), amplitude at 10 and 20 minutes (A10 and A20; VCM units), maximum clot firmness (MCF; VCM units), and lysis index (LI; %). Values were compared using a t-test or Wilcoxon-Mann-Whitney test, with a P-value < 0.05 considered significant. Variability between samples was calculated using Levene's test. The VCM kaolin activation resulted in significantly faster CT and CFT (P < 0.0001), higher alpha angle (P < 0.001), and higher A10 and A20 (P = 0.007, P = 0.015) compared to FWB. There was no difference in MCF, LI30, or LI45. There was no difference in variability identified. The addition of kaolin to recalcified citrated whole blood VCM samples results in more rapid clotting of FWB alone and could be considered for clinical use in dogs.

Application of thromboelastography in diagnosing normal pregnancies and pregnancies with complications

Background

This observational study aimed to compare the potential application of thromboelastography (TEG) in diagnosing women with normal pregnancy (NP) and women with threatened abortion (TA), missed abortion (MA), embryo arrest (EA), fetal death (FD), history of abnormal pregnancy (HAP), and antiphospholipid antibody syndrome (AA).

Methods

According to the relevant clinical criteria, patients were divided into groups, and their blood samples were subjected to TEG. Next, the parameters R, K, α‐angle, MA, LY‐30, G, and coagulation index (CI) were analyzed. Partial correlation analysis was used to analyze correlation between groups of data. LSD‐t test and Dunnett's T3 test were used to analyze continuous variables. Ordinal categorical variables were compared using ordinal logistic regression analysis and estimate odds ratio of risk factors. A receiver operating characteristic (ROC) curve was constructed to detect the ability of TEG to recognize various parameters, and areas under the curve were compared using Delong's test for diagnosing pregnancy‐related diseases.

Results

MA had a negative effect on the MA parameter in TEG; EA had a negative effect on the MA and G parameters; HAP had a negative effect on the CI parameter and a positive effect on the R parameter; AA had a negative effect on the CI parameter. Compared with that of the NP group, the G of the EA (p = 0.014) group and the CI of the TA (p = 0.036) MA (p = 0.08) EA (p = 0.026) HAP (p = 0.000004) and AA (p = 0.002) groups were reduced. In the ordinal logistic regression analysis, compared with that of the NP group, the high R value of the HAP group accounted for more than that of the NP group (OR = 48.76, p = 0.001); the high K value of the AA group accounted for more than that of the NP group (OR = 17.00, p = 0.023); the angle value distributions of the TA and AA groups were different from that of the NP group (OR = 3.30, p = 0.039; OR = 0.14, p = 0.029); the low MA value of the MA, EA, and HAP groups accounted for more than that of the NP group (OR = 0.16, p = 0.03; OR = 0.26, p = 0.005; OR = 0.11, p = 0.008); and the low CI value of the HAP group accounted for more than that of the NP group (OR = 0.09, p = 0.005). In the ROC analysis, there were no significant differences in the TEG parameters of pregnant women belonging to the NP and TA, NP and MA, NP and EA, NP and FD, NP and HAP, and NP and AA groups (p > 0.05).

Perioperative Coagulation Monitoring

The main goal of perioperative coagulation monitoring is to improve safety of patients undergoing surgical procedures. Various conditions can affect the coagulation system during surgery and bleeding. The value of traditional standard coagulation tests is limited in detecting hemostatic dysfunctions and they are particularly ineffective in diagnosing hyperfibrinolysis. This article reports on key issues and pathophysiologic changes that affect the hemostatic system in the perioperative setting. Values of preoperative coagulation tests are discussed and the basic principles for point-of-care coagulation devices, including platelet analyzers and their clinical use, are evaluated.