This is an update of the previous published guideline in 2006. It addresses the problem of thrombocytopenia developing in patients receiving heparin therapy and emphasises the importance of diagnosing heparin induced thrombocytopenia as a serious complication of therapy with a high morbidity and mortality. Because it is so important to diagnose there is first a section on monitoring of patients at high risk of developing HITT, although this is now recommended in a smaller number than in the 2006 guideline.

A clinical scoring system called the ‘4 T’s‘ is recommended as a preliminary assessment tool, to be used in conjunction with laboratory measurement of the causative antibodies.

The sensitivity and specificity of both the clinical and laboratory assessments are discussed and criteria for treatment suggested.

Therapy is based on the removal of all heparin exposure and its substitution with a non-cross-reacting anticoagulant at therapeutic levels. The guideline also considers special circumstances such as re-exposure to heparin and the problems of coronary interventions.

Declaration of Interests

The BSH paid the expenses incurred during the writing of this guidance. None of the authors had conflicts of interest to declare. All authors have made a declaration of interests to the BSH and Task Force Chairs which may be viewed on request.