A clinical-laboratory algorithm incorporating optical density value to predict heparin-induced thrombocytopenia

 

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Summary

The diagnosis of heparin-induced thrombocytopenia (HIT) is complex and involves integrating both clinical and laboratory findings. Readily available diagnostic tests such as the heparin-dependant antibody assay (HDAA) lack desired specificity when utilised alone. A diagnostic algorithm incorporating the 4T pretest probability score, HDAA, and optical density (OD) value was implemented as a tool to assist in the diagnosis of HIT and with the decision to treat patients. Patients with a 4T score >3 and/or positive HDAA result with an OD ≥1 were considered positive. Utilisation of this algorithm was hypothesised to improve the identification of patients without SRA confirmed HIT and improve overall specificity compared to other diagnostic strategies. Retrospective chart review was conducted and included patients with a positive or equivocal HDAA result and a serotonin release assay result during a two-year period. Each patient was evaluated for the diagnosis of HIT using the algorithm. The specificity and sensitivity of the diagnostic algorithm to identify subjects with SRA confirmed HIT was evaluated. A total of 83 patients were identified for inclusion in the study. The diagnostic algorithm identified 22 patients for direct thrombin inhibitor (DTI) therapy. Nine of these patients were SRA positive. The sensitivity of the algorithm was 0.9 with a specificity of 0.822. The diagnostic algorithm was found to be both more specific and sensitive than other diagnostic strategies including the 4T score alone, HDAA alone, and the combination of the 4T score and HDAA results. This preliminary data suggest a diagnostic algorithm combining 4T score, HDAA, and OD value may be a tool to aid in the identification SRA positive patients for DTI therapy.

• References

• 1 Warkentin TE, Greinacher A, Koster A. et al. Treatment and prevention of heparin-induced thrombocytopenia: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008; 133 (Suppl. 06) 340S-380S.
  CrossrefPubMedGoogle Scholar
• 2 Napolitano LM, Warkentin TE, Almahameed A. et al. Heparin-induced thrombocytopenia in the critical care setting: diagnosis and management. Crit Care Med 2006; 34: 2898-2911.
  CrossrefPubMedGoogle Scholar
• 3 Warkentin TE, Chong BH, Greinacher A. Heparin-induced thrombocytopenia: towards consensus. Thromb Haemost 1998; 79: 1-7.
  Article in Thieme ConnectPubMedGoogle Scholar
• 4 Warkentin TE. Heparin-induced thrombocytopenia: pathogenesis and management. Br J Haematol 2003; 121: 535-555.
  CrossrefPubMedGoogle Scholar
• 5 Warkentin TE. Platelet count monitoring and laboratory testing for heparin-induced thrombocytopenia. Arch Pathol Lab Med 2002; 126: 1415-1423.
  PubMedGoogle Scholar
• 6 Lo GK, Juhl D, Warkentin TE. et al. 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.
  CrossrefPubMedGoogle Scholar
• 7 Denys B, Stove V, Philippe J. et al. A clinical-laboratory approach contributing to a rapid and reliable diagnosis of heparin-induced thrombocytopenia. Thromb Res 2008; 123: 137-145.
  CrossrefPubMedGoogle Scholar
• 8 Wirth SM, Macaulay TE, Armitstead JA. et al. Evaluation of a Clinical Scoring Scale to Direct Early Appropriate Therapy in Heparin-Induced Thrombocytopenia. J Oncol Pharm Pract 2010; 16: 161-166.
  CrossrefPubMedGoogle Scholar
• 9 Warkentin TE, Hayward CP, Smith CA. et al. Determinants of donor platelet variability when testing for heparin-induced thrombocytopenia. J Lab Clin Med 1992; 120: 371-379.
  PubMedGoogle Scholar
• 10 Dager WE, Dougherty JA, Nguyen PH. et al. Heparin-induced thrombocytopenia: treatment options and special considerations. Pharmacotherapy 2007; 27: 564-587.
  CrossrefPubMedGoogle Scholar
• 11 Trossaert M, Gaillard A, Commin PL. et al. High incidence of anti-heparin/platelet factor 4 antibodies after cardiopulmonary bypass surgery. Br J Haematol 1998; 101: 653-655.
  CrossrefPubMedGoogle Scholar
• 12 Francis JL, Palmer 3rd GJ, Moroose R, Drexler A. Comparison of bovine and porcine heparin in heparin antibody formation after cardiac surgery. Ann Thorac Surg 2003; 75: 17-22.
  CrossrefPubMedGoogle Scholar
• 13 Zwicker JI, Uhl L, Huang WY. et al. Thrombosis and ELISA optical density values in hospitalized patients with heparin-induced thrombocytopenia. J Thromb Haemost 2004; 2: 2133-2137.
  CrossrefPubMedGoogle Scholar
• 14 Altuntas F, Matevosyan K, Burner J. et al. Higher optical density of an antigen assay predicts thrombosis in patients with heparin-induced thrombocytopenia. Eur J Haematol 2008; 80: 429-435.
  CrossrefPubMedGoogle Scholar
• 15 Untch B, Ahmad S, Jeske WP. et al. Prevalence, isotype, and functionality of antiheparin-platelet factor 4 antibodies in patients treated with heparin and clinically suspected for heparin-induced thrombocytopenia. The pathogenic role of IgG. Thromb Res 2002; 105: 117-123.
  CrossrefPubMedGoogle Scholar
• 16 Warkentin TE, Greinacher A. Heparin-induced thrombocytopenia: recognition, treatment, and prevention: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 311S-337S.
  CrossrefPubMedGoogle Scholar
• 17 Lewis BE, Wallis DE, Hursting MJ. et al. Effects of argatroban therapy, demographic variables, and platelet count on thrombotic risks in heparin-induced thrombocytopenia. Chest 2006; 129: 1407-1416.
  CrossrefPubMedGoogle Scholar
• 18 Lewis BE, Wallis DE, Berkowitz SD. et al. Argatroban anticoagulant therapy in patients with heparin-induced thrombocytopenia. Circulation 2001; 103: 1838-1843.
  CrossrefPubMedGoogle Scholar
• 19 Kiser TH, Burch JC, Klem PM. et al. Safety, efficacy, and dosing requirements of bivalirudin in patients with heparin-induced thrombocytopenia. Pharmacotherapy 2008; 28: 1115-1124.
  CrossrefPubMedGoogle Scholar
• 20 Janatpour KA, Gosselin RC, Dager WE. et al. Usefulness of optical density values from heparin-platelet factor 4 antibody testing and probability scoring models to diagnose heparin-induced thrombocytopenia. Am J Clin Pathol 2007; 127: 429-433.
  CrossrefPubMedGoogle Scholar
• 21 Whitlatch NL, Perry SL, Ortel TL. Anti-heparin/platelet factor 4 antibody optical density values and the confirmatory procedure in the diagnosis of heparin-induced thrombocytopenia. Thromb Haemost 2008; 100: 678-684.
  Article in Thieme ConnectPubMedGoogle Scholar
• 22 Pouplard C, Leroux D, Regina S. et al. Effectiveness of ne immuno-assay for the diagnosis of heparin-induced thrombocytopenia and improved specificity when detecting IgG antibodies. Thromb Haemost 2010; 103: 145-150.
  Article in Thieme ConnectPubMedGoogle Scholar
• 23 Legnani C, Cini M, Pili C. et al. Evaluation of a new automated panel of assays for the detection of anti-PF4/heparin antibodies in patients suspected of having heparin-induced thrombocytopenia. Thromb Haemost 2010; 104: 402-409.
  Article in Thieme ConnectPubMedGoogle Scholar