The HIT Calculator uses the 4T Score to estimate the risk of Heparin-Induced Thrombocytopenia and guide further testing and treatment.
4T Score for HIT Calculator
What is HIT Calculator?
The HIT Calculator is a clinical decision-support tool used to estimate the likelihood of Heparin-Induced Thrombocytopenia (HIT) in patients exposed to heparin. This tool is based on the widely accepted 4T Score Calculator, which evaluates four key clinical factors to guide further diagnostic testing and management.
Explore more Hematology calculators:
What Is the 4T Score?
The 4T Score stands for:
- Thrombocytopenia
- Timing of platelet count fall
- Thrombosis or other complications
- Other causes of low platelets
Each component is scored from 0 to 2, with a total score ranging from 0 to 8. Based on the total, the probability of HIT is categorized as low, intermediate, or high.
Why Use This HIT Calculator?
- Trusted in hospital, hematology, and internal medicine settings
- Helps assess the probability of HIT before ordering costly laboratory tests
- Supports early clinical decision-making
- Minimizes unnecessary discontinuation of heparin
4T score HIT refers to a clinical scoring system used to estimate the probability of Heparin-Induced Thrombocytopenia (HIT) in patients receiving heparin. It evaluates four key factors: thrombocytopenia, timing of platelet fall, thrombosis or other events, and the presence of other causes of low platelets. The total score helps categorize patients into low, intermediate, or high risk for HIT, guiding further diagnostic decisions.
The 4T score calculator is a clinical tool used to quickly determine the likelihood of HIT based on the 4T score system. By assigning 0–2 points for each of the four criteria, the calculator provides a total score (0–8), which correlates with the probability of HIT. A low score suggests HIT is unlikely, while a high score indicates a strong possibility requiring urgent action and further testing.
HIT score interpretation involves analyzing the total points obtained from the 4T score.
- 0–3 points: Low probability of HIT (≤5%) – No further testing usually needed.
- 4–5 points: Intermediate probability (~10–20%) – Consider laboratory testing.
- 6–8 points: High probability (>50%) – Stop heparin immediately and initiate confirmatory testing and alternative anticoagulation.
Proper interpretation is crucial to avoid both over- and under-treatment.
The HIT Expert Probability score is an advanced clinical tool that incorporates additional patient-specific details and expert clinical judgment to assess the likelihood of HIT. While the 4T score is widely used for initial assessment, the Expert Probability score may be used in complex cases or research settings to improve diagnostic accuracy and guide personalized decision-making.