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Observational Study
. 2021 Jul 1;32(5):328-334.
doi: 10.1097/MBC.0000000000001042.

Evaluation of 4Ts score inter-rater agreement in patients undergoing evaluation for heparin-induced thrombocytopenia

Kalynn A Northam  1 , William F Parker  2 , Sheh-Li Chen  1 , Jonathan D Cicci  1 , Feng-Chang Lin  3 , Marian A Rollins-Raval  4 , Raj S Kasthuri  5   6
Affiliations
Observational Study

Evaluation of 4Ts score inter-rater agreement in patients undergoing evaluation for heparin-induced thrombocytopenia

Kalynn A Northam et al. Blood Coagul Fibrinolysis. .

Abstract

The American Society of Hematology and American College of Chest Physicians heparin-induced thrombocytopenia guidelines recommend calculation of a pretest probability score prior to performing laboratory testing, and the 4Ts score is commonly used. Inter-rater agreement of the 4Ts score has been evaluated, but limited data are available regarding the reliability of the 4Ts score when performed by nonexpert clinicians. The purpose of this study was to Compare 4Ts scores calculated by medical teams to an expert. A single-center observational study was conducted in patients evaluated for heparin-induced thrombocytopenia over 24 months. The primary outcome was difference in mean 4Ts score calculated by the medical team compared with an expert. Secondary outcomes included inter-rater agreement in risk category assignment and the negative predictive value (NPV) of the 4Ts score. The mean total 4Ts score was significantly higher when calculated by the medical team compared with expert (4.16 ± 1.41 versus 3.42 ± 1.53; P < 0.001). There was slight agreement in risk category assignment (Cohen κ coefficient = 0.164; P = 0.005). The NPV of the 4Ts score was 0.949 (95% confidence interval 0.891-1.000) when calculated by the medical team and 0.927 (95% confidence interval 0.869-0.984) when calculated by expert. Total 4Ts scores calculated by the medical team were significantly higher with only slight inter-rater agreement compared with expert. The NPV of the 4Ts score when calculated by nonexperts may be lower than previously reported. The recommendation to forgo laboratory testing for low 4Ts score patients may need to be revisited.

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References

    1. Cuker A, Arepally GM, Chong BH, Cines DB, Greinacher A, Gruel Y, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopenia. Blood Adv 2018; 2:3360–3392.
    1. Linkins LA, Dans AL, Moores LK, Bona R, Davidson BL, Schulman S, Crowther M. Treatment and prevention of heparin-induced thrombocytopenia: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest 2012; 141:e495S–e530S.
    1. Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A. Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings. J Thromb Haemost 2006; 4:759–765.
    1. Cuker A, Arepally G, Crowther MA, Rice L, Datko F, Hook K, et al. The HIT Expert Probability (HEP) Score: a novel pretest probability model for heparin-induced thrombocytopenia based on broad expert opinion. J Thromb Haemost 2010; 8:2642–2650.
    1. Strutt JK, Mackey JE, Johnson SM, Sylvia LM. Assessment of the 4Ts pretest clinical scoring system as a predictor of heparin-induced thrombocytopenia. Pharmacotherapy 2001; 31:138–145.

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