ToolsCalculators
HIT Expert Probability (HEP) score
Pre-test probability of heparin-induced thrombocytopenia.
HIT Expert Probability (HEP) score
Magnitude of platelet count fall
Timing of platelet count fall
Use the rapid-onset rows only if heparin was given within the past 100 days.
Nadir platelet count
Thrombosis
Skin necrosis at subcutaneous injection site
Acute systemic reaction after IV heparin bolus
Bleeding, petechiae, or extensive haematoma
Other cause of thrombocytopenia
Result5 points
Score >=5 indicates a higher probability of HIT (100% sensitivity, 60% specificity in the validation cohort); continue empiric management and send a HIT immunoassay.
When to use
- Estimating the probability of heparin-induced thrombocytopenia in a patient with a falling platelet count on heparin.
Formula
Weighted sum of magnitude and timing of platelet fall, nadir, thrombosis, skin necrosis, systemic reaction, bleeding, and other causes. Positive and negative points; cutoff >=5 suggests HIT.
Pearls and pitfalls
- Designed to complement, not replace, a confirmatory HIT immunoassay and functional assay.