Comparison of Viscoelastic Testing by Rotational Torsion and Harmonic Resonance Methods.

OBJECTIVES: To compare the performance of the TEG 5000 and TEG 6S Global Hemostasis cartridge. METHODS: We reviewed validation data of the TEG 5000 and TEG 6S Global Hemostasis cartridge. The specimens were analyzed in parallel according to the manufacturer's operating instructions. RESULTS: Fifty-four healthy donors and 13 donors with known hemostatic abnormalities were included. The correlations between instrument types were only moderate-the Spearman rank correlations were 0.55, 0.62, 0.64, and 0.72, respectively, for CK R, K, angle, and maximum amplitude (MA) parameters. Using the manufacturer's device-specific reference ranges to classify results as normal/abnormal, there was weak agreement in the qualitative interpretation of all parameters (Cohen's κ for agreement for CK R, K, angle, and MA was 0.418, 0.154, -0.083, and 0.127, respectively). This could lead to discordant transfusion decisions. CONCLUSIONS: These findings indicate that the TEG 5000 and TEG 6S may not be used interchangeably.

Potential impact of a delayed ADAMTS13 result in the treatment of thrombotic microangiopathy: an economic analysis.

BACKGROUND: A pre-plasma exchange ADAMTS13 measurement differentiates thrombotic thrombocytopenic purpura (TTP) from other forms of thrombotic microangiopathy (TMA). Given that many hospitals do not perform the ADAMTS13 assay in-house and that the turnaround time (TAT) differs among reference laboratories, we performed an analysis investigating the potential impact of a delay in obtaining the results on the healthcare system. METHODS: An economic model was developed to estimate the impact of a delay in obtaining the pretreatment ADAMTS13 results on patients admitted with TMA with cost (US dollars) as the primary outcome. Incremental cost-effectiveness ratio (ICER) as a composite outcome was calculated from both cost and life days [LDs], an effectiveness surrogate marker. Model parameters were gathered from the medical literature, except for the institutional cost of the ADAMTS13 test. RESULTS: In patients with TMA, during the 6-day study period, the incremental cost to the healthcare system ranged from approximately $4155 to $5123 for every 1-day delay in obtaining the pre-exchange ADAMTS13 results with virtually no change in the effectiveness marker. The ICER composite outcome established the cost-effectiveness of having a fast TAT for pre-exchange ADAMTS13 results. Probabilistic sensitivity analyses also confirmed the robustness of the model. CONCLUSIONS: In patients with clinical presentations of TMAs, having a rapid TAT for pre-exchange ADAMTS13 measurement appeared to be cost-effective. If testing cannot be performed in-house, then our findings support the necessity of contracting with a reference laboratory that can reliably provide the result, preferably within 1 day of admission.

An economic analysis of different treatments for bleeding in patients with acquired haemophilia.

BACKGROUND: Acquired haemophilia A (AHA), with potentially high risk of morbidity and mortality, occurs as a result of inhibitors against factor VIII. Bleeding due to AHA can be treated with activated prothrombin complex concentrate (aPCC), recombinant activated factor VII (rFVIIa) or recently, recombinant porcine-sequence factor VIII (rpFVIII). We extended our previous cost-effectiveness analysis (CEA) comparing rpFVIII against the available traditional options. METHODS: For high-titred, haemorrhaging AHA patients treated with either aPCC, rFVIIa or rpFVIII, over the course of 6-days, a Markov simulation was conducted to evaluate the outcomes when these patients transitioned into any of the four following health states: (1) continuous bleeding, (2) thrombosis, (3) stop bleeding and (4) death, with states (2), (3) and (4) modelled as absorbing states. All model parameters were obtained from the medical literature, except the costs of aPCC, rFVIIa and the factor VIII assay, which came from our institutional data. RESULTS: Excluding the cost of the initial treatment on day 0, the total subsequent treatment cost of rFVIIa was substantially more than the costs of aPCC and rpFVIII ($13 925 vs. $1778 vs. $6957, respectively). The average quality-adjusted life days (QALDs) gained from rpFVIII was lowest (4·89 vs. 4·9 for rFVIIa and 4·91 for aPCC). Overall, aPCC dominated the other two treatments. The model was determined to be robust across the tested ranges for all input variables. CONCLUSION: Based on this economic model, for AHA patients with high titres who were bleeding, aPCC was the most cost-effective treatment option and may be considered for use if there is no clinical contraindication.