For healthcare professionals

Khorana score calculator

The Khorana score estimates the risk of venous thromboembolism (a blood clot in a vein, such as a deep vein thrombosis or pulmonary embolism) in adults with cancer who are starting chemotherapy, from the cancer site, three blood counts and body mass index. This tool is written for clinicians. It is not a self-check and not a diagnosis.

Last reviewed: 2026-11-03 By the uncovermyrisk.com editorial team Educational only, not medical advice.

Patient findings

For an adult outpatient with cancer about to start chemotherapy, using the blood counts taken before chemotherapy. Nothing you enter leaves this page.

Cancer site

Very high risk: stomach or pancreas High risk: lung, lymphoma, gynecologic, bladder or testicular Any other site

Platelet count (x10^9/L, 1 to 2000) Hemoglobin (g/dL, 2 to 25)

Using an erythropoiesis-stimulating agent (ESA)

No Yes

Leukocyte (white cell) count (x10^9/L, 0.1 to 200) Body mass index (kg/m2, 10 to 90)

Result appears here

What you will see

The total Khorana score from 0 to 6, the points for each item, the risk group and the published VTE rates for that group.

Educational only, not medical advice. A score never replaces the judgment of the treating team.

Source

The Khorana score by Khorana AA and colleagues, Blood 2008, with the items, points, risk groups and VTE rates as printed in the open access review by Nusrat and colleagues, International Journal of Molecular Sciences 2026 (section 4.1 and Table 2, CC BY 4.0). The tests check each item, the site points, the four lab and BMI edges, the maximum of 6 and the group for every score.

Validated in

Adult outpatients with cancer who had not yet received chemotherapy and were expected to have at least four cycles, in a prospective study with a derivation cohort of 2701 and a validation cohort of 1365 patients. We cite the 2008 paper but do not quote it, because its license does not allow reuse here.

Limits

For ambulatory patients starting chemotherapy, not for patients in hospital (see the Padua score) or around surgery (see the Caprini score). The rates are group figures from the original cohorts over a short follow-up, not a prediction for one patient. In a Korean cohort of 11,714 patients, the rates by group were lower than in the original study. The review prints the high group as both '3 or more' (Table 2) and '> 3' (text) and the BMI item as both '35 or more' (text) and '> 35' (Table 2); we use 3 or more and 35 or more, which match the 0, 1 to 2 and 3 or more groups. A platelet count of 350 and a BMI of 35 count; a hemoglobin of 10 and a leukocyte count of 11 do not.

The point table

Khorana score, as printed in Nusrat and colleagues 2026 (Nusrat 2026) (Khorana 2008):

Very high risk cancer site (stomach or pancreas): 2
High risk cancer site (lung, lymphoma, gynecologic, bladder or testicular): 1
Platelet count 350 x10^9/L or more before chemotherapy: 1
Hemoglobin under 10 g/dL, or use of an erythropoiesis-stimulating agent: 1
Leukocyte count over 11 x10^9/L before chemotherapy: 1
Body mass index 35 kg/m2 or more: 1

Any other cancer site scores 0 for the site item. The total ranges from 0 to 6. Worked example: a patient with lung cancer (1), a platelet count of 380 (1), a hemoglobin of 11.2 g/dL with no ESA (0), a leukocyte count of 9 (0) and a BMI of 28 (0) scores 2, the intermediate group.

Risk groups and VTE rates

The review gives the VTE rates by group in the original derivation and validation cohorts (Nusrat 2026) (Khorana 2008):

Low risk, score 0: 0.8% (derivation) and 0.3% (validation)
Intermediate risk, score 1 to 2: 1.8% and 2%
High risk, score 3 or more: 7.1% and 6.7%

Overall, 2.2% of the derivation cohort had a VTE over a median follow-up of 73 days, and the C-statistic was 0.7 in both cohorts (Nusrat 2026). The review notes that external validation studies found a C-statistic of 0.61 and 0.52 (Nusrat 2026).

Reading the result

In a Korean study of 11,714 patients starting ambulatory chemotherapy, the 6-month VTE rate was 0.77% with a score of 0, 2.26% with 1 to 2 and 4.16% with 3 or more (Ha 2023). That study found a platelet count of 350 or more was not independently linked to VTE, and very few patients had a BMI of 35 or more (Ha 2023). The review lists a Khorana score of 2 or more among the indications for primary prevention of VTE in ambulatory patients with cancer (Nusrat 2026). The score supports a decision about clot prevention; it does not make that decision on its own.

Related tools

For adults admitted to a medical ward, see the Padua prediction score or the IMPROVE VTE risk score; around surgery, the Caprini score. When a clot is already suspected, see the Wells score for DVT and the Wells score for PE. For the risk of a new clot after anticoagulation for a first unprovoked clot stops, see the DASH score. For fever with a low neutrophil count during chemotherapy, see the MASCC risk index. Other bedside scores are listed under For healthcare professionals.

Sources

Nusrat S, Khan S, Beg K, Raskob G. Unmet needs and challenges in cancer-associated venous thromboembolism. Int J Mol Sci. 2026;27(4):1756. doi:10.3390/ijms27041756. PMID 41751895. Open access (CC BY 4.0). pmc.ncbi.nlm.nih.gov/articles/PMC12940439/
Khorana AA, Kuderer NM, Culakova E, Lyman GH, Francis CW. Development and validation of a predictive model for chemotherapy-associated thrombosis. Blood. 2008;111(10):4902-4907. doi:10.1182/blood-2007-10-116327. PMID 18216292. Cited, not quoted. doi.org/10.1182/blood-2007-10-116327
Ha H, Ko YH, Kim K, et al. Application of the Khorana score for cancer-associated thrombosis prediction in patients of East Asian ethnicity undergoing ambulatory chemotherapy. Thromb J. 2023;21:63. doi:10.1186/s12959-023-00505-3. PMID 37271814. Open access (CC BY 4.0). pmc.ncbi.nlm.nih.gov/articles/PMC10240689/

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.