Our approach to the diagnosis and initial management of patients with suspected HIT. Our approach is based primarily on clinical assessment, however imprecise, and complemented by the results of HIT laboratory tests, which are also limited by technical imprecision and uncertain specificity. *Estimates of the clinical probability of HIT in an individual patient may change over time. Therefore, it is our practice to frequently reevaluate patients in whom diagnostic uncertainty exists and to adjust treatment accordingly.