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External validation of the HIT Expert Probability (HEP) score.
Lee Joseph, Marcelo P V Gomes, Firas Al Solaiman
1Esther S. H. Kim, MD, MPH, Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, 9500 Euclid Avenue/J3-5, Cleveland, OH 44195, USA, Tel.: +1 216 444 1680, Fax: +1 216 636 6958,
The HIT Expert Probability (HEP) score shows similar diagnostic accuracy to the 4T score for heparin-induced thrombocytopenia (HIT). Further validation of the HEP score is needed before widespread clinical use.
Area of Science:
- Hematology
- Clinical Diagnostics
- Thrombosis Research
Background:
- Heparin-induced thrombocytopenia (HIT) diagnosis is complex.
- The HIT Expert Probability (HEP) score was developed to assist HIT diagnosis.
- External validation of the HEP score is necessary.
Purpose of the Study:
- To prospectively validate the diagnostic performance of the HEP score.
- To compare the HEP score with the 4T score in a real-world clinical setting.
- To assess the clinical utility of the HEP score for HIT diagnosis.
Main Methods:
- Prospective validation of the HEP score in 51 patients evaluated for possible HIT.
- Independent application of 4T and HEP scores by Vascular Medicine fellows.
- HIT diagnosis adjudicated by expert review and confirmed by laboratory testing (serotonin release assay and anti-PF4/heparin ELISA).
Main Results:
- No significant difference in diagnostic accuracy between the 4T and HEP scores (AUC 0.74 vs 0.73, p=0.97).
- HEP score (≥2) demonstrated 100% sensitivity and 16% specificity.
- 4T score (>3) showed 93% sensitivity and 35% specificity for confirmed HIT.
Conclusions:
- Both 4T and HEP scores are effective screening tools for HIT.
- The diagnostic performance of both scores is comparable when validated against confirmatory testing and expert opinion.
- The complexity of the HEP score necessitates further validation before clinical adoption.
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