Erences in the distributions of results for enoxaparin and tinzaparin, taking into account inter-individual variation and differing concentrations of LMWH. Box and whisker diagrams were constructed using R's boxplot function. Boxes span the interquartile range 2-Bromo-4-fluoro-5-methylbenzoic acid and the whiskers encompass the data point furthest from the box yet within 1.5 times the length of the box from the box.ROTEM and FOR's tests for clot lysis showed a tentative dose responseResults Raw data of our results are available as a text file in `Additional file 1'.Measures of clot initiation were prolonged by increasing doses of LMWHNeither our ROTEM-ML nor FOR-ClotSR results were outside the reference ranges for a normal level of fibrinolysis, and there were no significant differences between enoxaparin and tinzaparin at any concentration, or in ANOVA whole-data analysis. There was, however, a significant but weak negative correlation between the dose of enoxaparin and ROTEM-ML ( = -0.36, P < 0.05); and the dose of tinzaparin and FOR-Clot SR ( = -0.41, P < 0.05), but not between the dose of enoxaparin and FOR-Clot SR or tinzaparin and ROTEM-ML (see Table 1 and Fig. 2e and f ).Measures of initiation of coagulation as assessed by ROTEM and FOR were significantly prolonged by increasing concentrations of both LMWH's PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/12027669 (ROTEMCT, FOR-COT1 and FOR-COT2: see Table 1 and Fig. 2a-c), with significant correlation coefficients (Spearman's Rho) PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/20460822 of between 0.54 and 0.77, but there was a wide spread of results, with the lowest measured ROTEM-CT in the presence of 1.5 IU/mL tinzaparin being shorter than the longest ROTEM-CT in the control group (0 IU/mL tinzaparin). The two LMWH's values of ROTEM-CT correlated 1-Bromo-2-fluoro-4-methoxy-5-nitrobenzene to each other significantly, as did their values of FOR-COT1 and FOR-COT2 (see Figs. 3a,b and d).FOR-(COT2-COT1) was the only measure of clot propagation that showed a dose esponse to LMWHROTEM-alpha angle, ROTEM-CFT and FOR-Slope were not affected by increasing concentrations of LMWH (see Table 1 and Fig. 2d and g). FOR-(COT2-COT1), which is the time delay between when viscosity starts to increase (COT1) and when elasticity starts to increase (COT2), was significantly prolonged by increasing doses of LMWH. The median (COT2-COT1) in the presence of 1.5 IU/mL tinzaparin and enoxaparin were 50 and 30 respectively longer than in the absence of added LMWH, giving correlation coefficients (Spearman's Rho) of 0.47 and 0.79 respectively (P < 0.05). Although the differences between (COT2-COT1) for the two LMWH's at each concentration were not significantly different, there was a significant whole-data difference in the results for tinzaparin and enoxaparin (see Table 1 and Fig. 2h). ROTEM-MCF and FOR-G'max for enoxaparin and tinzaparin showed good correlation (see Fig. 3e-f ) but were not affected by increasing doses of either LMWH (see Table 1).Discussion Miyazaki et al. estimated that around 70 of spinal hematomas occurring at the time of withdrawing an epidural catheter were related to abnormal coagulation, which challenges the dogma that monitoring of prophylactic LMWH is unnecessary in this setting [7]. Due to the difficulty and expense involved in conducting prospective studies on rare complications, it is very unlikely that such a study will ever be able to show that viscoelastic tests are reliable predictors of spinal haematoma. The most common and well-documented clinical viscoelastic tests are thrombelastography (TEG? and rotational thromboelastometry (ROTEM?. Less well-docu.