For healthcare professionals
ORBIT bleeding score calculator
The ORBIT bleeding score adds points for five factors linked to major bleeding in people with atrial fibrillation (AFib) who take an oral anticoagulant (blood thinner). This tool is written for clinicians and is not a diagnosis.
Patient details
For people with AFib on, or considering, an oral anticoagulant. Nothing you enter leaves this page.
What you will see
The total ORBIT score from 0 to 7, its risk group and the points for each factor.
Educational only, not medical advice. Never start, stop or skip a blood thinner on your own.
Source
The ORBIT bleeding score by O'Brien EC and colleagues, European Heart Journal 2015, with the items and points as printed in the open access Table 1B of Pastori and colleagues, Frontiers in Cardiovascular Medicine 2019 (CC BY 4.0). The risk groups and bleeding rates are as printed in Wang and colleagues, Oncotarget 2017 (CC BY 3.0), quoting the original paper. The tests check each item, the maximum of 7, the group edges and the age 75 and eGFR 60 edges.
Validated in
As Pastori and colleagues describe it, the score was derived in 7,411 people with AFib in the ORBIT-AF registry and tested in 14,264 people from the ROCKET-AF trial. We do not describe the original paper further, because its license does not allow reuse here.
Limits
Only for people with AFib. It counts bleeding risk factors; it does not estimate stroke risk or weigh the benefit of a blood thinner. Its accuracy (c-index) was 0.67 in the ORBIT registry and 0.62 in ROCKET-AF. The bleeding rates are group averages from the derivation registry, not a personal prediction; a 2017 meta-analysis found the score under-predicted major bleeding in all three groups in later studies. The two open sources differ: Pastori Table 1B gives age 75 or older and 2 points each for anemia and bleeding history, while Wang Table 1 lists age 74 or older and says 1 point for each risk factor. We follow Pastori, which matches the maximum of 7 and the group cut points. Age 75 counts (75 or older); eGFR 60 does not (under 60). The open table prints the hemoglobin unit as mg/dL; hemoglobin is measured in g/dL, so we show g/dL.
The point table
ORBIT bleeding score, as printed in Pastori and colleagues 2019, Table 1B (Pastori 2019) (O'Brien 2015):
- Reduced hemoglobin (under 13 in men, under 12 in women) or hematocrit (under 40% in men, under 36% in women), or a history of anemia: 2
- Bleeding history: 2
- Older age, 75 years or more: 1
- eGFR under 60 mL/min/1.73 m²: 1
- Antiplatelet drug use: 1
The name spells the items: Older age, Reduced hemoglobin, Bleeding history, Insufficient kidney function and Treatment with antiplatelets. The maximum is 7.
Worked example: a 78-year-old (1) with an eGFR of 52 (1) who takes aspirin (1), with normal hemoglobin and no past bleeding, scores 3, the intermediate group.
Risk groups
As printed in Wang and colleagues 2017, quoting the original paper, the total is grouped as low (0 to 2 points), intermediate (3) and high (4 or more), and the derivation reported adjusted major bleeding rates (events per 100 patient-years) of 2.4 (low), 4.7 (intermediate) and 8.1 (high) (Wang 2017) (O'Brien 2015).
- 0 to 2 points: low, 2.4 major bleeds per 100 patient-years
- 3 points: intermediate, 4.7 per 100 patient-years
- 4 to 7 points: high, 8.1 per 100 patient-years
In the same meta-analysis of later studies, the score under-predicted major bleeding in all three groups, and its accuracy (pooled C-statistic 0.65) was similar to HAS-BLED (0.63) (Wang 2017).
Reading the result
Pastori and colleagues report that in the ORBIT registry the score separated people who bled from people who did not with a c-index of 0.67, a little better than HAS-BLED (0.64) and close to the ATRIA score (0.66), with lower values in ROCKET-AF (0.62, 0.59 and 0.60) (Pastori 2019). They add that none of these scores is accurate enough to be the gold standard, and that guidelines advise checking known bleeding risk factors, both those that can be changed (such as antiplatelet medicines and uncontrolled blood pressure) and those that cannot (such as age and past major bleeding) (Pastori 2019).
The 2023 US atrial fibrillation guideline says that in people at high risk of stroke, bleeding risk scores should not be used on their own to decide whether to take an anticoagulant, but to find and change bleeding risk factors and to inform the decision (ACC/AHA 2023). General safety advice (not part of the score): never stop, skip or change a blood thinner because of a score. Talk to the clinician who prescribes it.
Related tools
For other bleeding scores, see the HAS-BLED score and, for people on warfarin, the ATRIA bleeding score; for older adults with AFib, the HEMORR2HAGES score; for stroke risk with AFib, CHA2DS2-VASc explained and the stroke risk check. To estimate kidney function first, use the eGFR calculator. Other bedside scores are listed under For healthcare professionals.
Sources
- Pastori D, Menichelli D, Gingis R, Pignatelli P, Violi F. Tailored practical management of patients with atrial fibrillation: a risk factor-based approach. Front Cardiovasc Med. 2019;6:17. doi:10.3389/fcvm.2019.00017. PMID 30915342. Open access (CC BY 4.0). Table 1B (ORBIT items and points). pmc.ncbi.nlm.nih.gov/articles/PMC6422871/
- Wang C, Yu Y, Zhu W, Yu J, Lip GYH, Hong K. Comparing the ORBIT and HAS-BLED bleeding risk scores in anticoagulated atrial fibrillation patients: a systematic review and meta-analysis. Oncotarget. 2017;8(65):109703-109711. doi:10.18632/oncotarget.19858. PMID 29312640. Open access (CC BY 3.0). Methods and Table 1 (ORBIT risk groups and the derivation bleeding rates). pmc.ncbi.nlm.nih.gov/articles/PMC5752553/
- O'Brien EC, Simon DN, Thomas LE, Hylek EM, Gersh BJ, Ansell JE, et al. The ORBIT bleeding score: a simple bedside score to assess bleeding risk in atrial fibrillation. Eur Heart J. 2015;36(46):3258-3264. doi:10.1093/eurheartj/ehv476. PMID 26424865. Cited, not quoted. doi.org/10.1093/eurheartj/ehv476
- Joglar JA, Chung MK, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. J Am Coll Cardiol. 2024;83(1):109-279. doi.org/10.1016/j.jacc.2023.08.017
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-11-03. Spotted an error? See About.