Khorana score: the five predictors and how the points add up

The Khorana score adds points for five predictors measured before chemotherapy starts: cancer site (2 points for a very high-risk site such as stomach or pancreas, 1 for a high-risk site such as lung, lymphoma, gynecologic, bladder or testicular), a platelet count of 350 × 10⁹/L or more (1), hemoglobin below 10 g/dL or use of an ESA (1), a white cell count above 11 × 10⁹/L (1), and a body mass index of 35 or more (1). The maximum is 6. Pancreatic cancer with a platelet count of 350 scores 2 + 1 = 3.

This page doesn't give a cutoff. Magent's calculator also returns a low/intermediate/high group, but this page explains how the total is built, not what a total means or what to do with it.

Not a medical device. Not a diagnosis or dosing recommendation.

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Infection and VTE calculators
Khorana AA et al. · 2008
The Khorana formula
Worked examples
Khorana reference values
Frequently asked questions

What is the Khorana score?

The Khorana score is a predictive model for chemotherapy-associated venous thromboembolism (blood clots in the veins) in people with cancer. It was published by Alok A. Khorana and colleagues in Blood in 2008. It's also called the Khorana risk score or Khorana VTE score.

The 2008 abstract says the authors "developed a simple model for predicting chemotherapy-associated VTE using baseline clinical and laboratory variables."

This page explains each predictor and how the points add up. It doesn't say what a given total means, and the score doesn't diagnose a blood clot.

The Khorana formula

Khorana = site points (very_high 2, high 1, other 0)
        + (platelets_10e9_l >= 350 ? 1 : 0)
        + (hemoglobin_g_dl < 10 OR ESA ? 1 : 0)
        + (wbc > 11 × 10⁹/L ? 1 : 0)
        + (bmi_ge_35 ? 1 : 0)

Exact expression the calculator uses:

Khorana = cancer_site (very_high 2, high 1, other 0) + (platelets>=350) + (hemoglobin<10 g/dL or ESA) + (wbc>11 x10^9/L) + (BMI>=35); max 6; 0 low, 1-2 intermediate, >=3 high

Maximum: 6.

The five predictors

Predictor	Input	Points
Cancer site, very high risk (stomach, pancreas)	`cancer_site` = `very_high`	2
Cancer site, high risk (lung, lymphoma, gynecologic, bladder, testicular)	`cancer_site` = `high`	1
Any other site	`cancer_site` = `other`	0
Platelets 350 × 10⁹/L or more	`platelets_10e9_l`	1
Hemoglobin below 10 g/dL, or ESA use	`hemoglobin_g_dl` or `hemoglobin_g_l`, plus the ESA flag	1
White cell count above 11 × 10⁹/L	`wbc_k_ul` or `wbc_ul`	1
Body mass index 35 or more	`bmi_ge_35` (true/false)	1

ESA stands for erythropoiesis-stimulating drug, a medicine that stimulates red blood cell production. The site lists are from Magent's record; the caller picks the class, and Magent doesn't assign it from histology text.

How to calculate the Khorana score

Cancer site. Very high-risk site: 2. High-risk site: 1. Other: 0.
Platelets. 350 × 10⁹/L or more scores 1. 350 scores; 349 doesn't.
Hemoglobin or ESA. Hemoglobin below 10 g/dL scores 1. ESA use scores 1. Both together still score 1, not 2. Hemoglobin of exactly 10.0 doesn't score unless an ESA is used.
White cells. Above 11 × 10⁹/L scores 1. Exactly 11.0 doesn't.
BMI. 35 or more scores 1. The caller answers true or false; Magent doesn't take height or weight.
Add everything. The total is 0 to 6.

Units

Hemoglobin: g/dL, or g/L divided by 10. So 100 g/L is 10.0 g/dL and doesn't score.
White cells: thousands per µL (the same as 10⁹/L), or cells per µL. 11 × 10⁹/L is 11,000/µL. 11,001/µL scores; 11,000 doesn't.
Platelets: × 10⁹/L.

What the calculator returns

Magent's calculator returns the total, the maximum of 6, the values it used (site class, platelets, hemoglobin in g/dL, ESA flag, white cells in cells/µL, BMI flag), a line for each item and a low/intermediate/high group. This page doesn't interpret the group.

Worked examples

These use Magent's own expected values for the calculator. Unless stated, the site is "other," platelets 200, hemoglobin 12 g/dL with no ESA, white cells 8 × 10⁹/L and the BMI flag false.

Example 1: nothing scores

Site other → 0; platelets 200 → 0; hemoglobin 12, no ESA → 0; white cells 8 → 0; BMI flag false → 0.
Khorana = 0 (of 6).

Example 2: very high-risk site

Site very high → 2.
Khorana = 2.

Example 3: hemoglobin 10.0 vs 9.9

Hemoglobin 10.0, no ESA → 0: Khorana = 0.
Hemoglobin 9.9 → 1: Khorana = 1.

Example 4: low hemoglobin and an ESA

Hemoglobin 9.9 and ESA use → still 1, not 2.
Khorana = 1.

Example 5: white cells 11.0 vs 12

White cells 11.0 × 10⁹/L → 0: Khorana = 0.
White cells 12 × 10⁹/L → 1: Khorana = 1.

Example 6: very high-risk site and platelets 350

Site very high → 2.
Platelets 350 → 1.
Khorana = 3.

Example 7: everything scores

Site very high → 2; platelets 350 → 1; hemoglobin 9.9 with ESA → 1; white cells 12 → 1; BMI flag → 1.
Khorana = 6.

Khorana reference values

These are Magent's expected values for the calculator, with the other inputs at their defaults. No predictors scores 0. A high-risk site scores 1 and a very high-risk site scores 2. Platelets of 350, hemoglobin of 9.9 g/dL, white cells of 12 × 10⁹/L (or 11,001/µL) and BMI 35 or more each score 1. Hemoglobin of 10.0 g/dL (100 g/L) and white cells of 11.0 × 10⁹/L score 0. ESA use scores 1 with hemoglobin of either 10.0 or 9.9. A very high-risk site with platelets of 350 scores 3, and all five predictors score 6.

History of the Khorana score

The score comes from Alok A. Khorana, Nicole M. Kuderer, Eva Culakova, Gary H. Lyman and Charles W. Francis, Development and validation of a predictive model for chemotherapy-associated thrombosis, Blood, 2008 (volume 111, issue 10, pages 4902–4907).

The abstract sets out the problem: "Risk of venous thromboembolism (VTE) is elevated in cancer, but individual risk factors cannot identify a sufficiently high-risk group of outpatients." The model was characterized "in a derivation cohort of 2701 cancer outpatients from a prospective observational study" and then tested "in an independent cohort of 1365 patients from the same study."

It lists the five predictors with their points: "site of cancer (2 points for very high-risk site, 1 point for high-risk site), platelet count of 350 x 10(9)/L or more, hemoglobin less than 100 g/L (10 g/dL) and/or use of erythropoiesis-stimulating [drugs], leukocyte count more than 11 x 10(9)/L, and body mass index of 35 kg/m(2) or more (1 point each)." Those match Magent's calculator.

When it's used

The 2008 study looked at cancer outpatients starting chemotherapy, using baseline (pre-chemotherapy) values. Magent's record describes the same setting.

Where it's used

The cohorts came from a prospective observational study of cancer outpatients.

Who uses it

The abstract frames it as a model for identifying outpatients with cancer at higher short-term risk of venous thromboembolism.

Limits of the calculation

It adds five predictors. It doesn't diagnose a blood clot.
It's the Khorana 2008 model. It isn't the Padua or Caprini score.
Cancer site class is the caller's call; Magent doesn't read histology.
BMI 35 or more is a yes/no flag; Magent doesn't calculate BMI.
Low hemoglobin and ESA use score once together, not twice.
The calculator returns a group alongside the total. This page doesn't give a cutoff or say what any total means.

Clinical decisions belong to a qualified clinician who knows the patient.

Padua score is a VTE risk score for hospitalized medical patients, from age and ten caller-assigned findings, not for outpatients starting chemotherapy.
Wells DVT is a probability score for a suspected deep vein thrombosis that's already being considered, not a prediction before chemotherapy.

Glossary

VTE: venous thromboembolism, a blood clot in a vein (deep vein thrombosis or pulmonary embolism).
Platelets: blood cells involved in clotting.
Hemoglobin: the oxygen-carrying protein in red blood cells.
Leukocytes: white blood cells.
BMI: body mass index, weight in kilograms divided by height in meters squared.
ESA: a medicine that stimulates the body to make red blood cells.

Common mistakes

Scoring low hemoglobin and ESA as 2. They're one item, worth 1.
Scoring hemoglobin of exactly 10.0. It has to be below 10 g/dL (unless an ESA is used).
Scoring a white count of exactly 11. It has to be above 11 × 10⁹/L.
Mixing up g/L and g/dL. 100 g/L is 10.0 g/dL.
Giving every cancer site points. Sites outside the very high and high lists score 0.

Source

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

Frequently asked questions

How do you calculate the Khorana score?

Add 2 for a very high-risk cancer site or 1 for a high-risk site, then 1 each for platelets 350 × 10⁹/L or more, hemoglobin below 10 g/dL or ESA use, white cells above 11 × 10⁹/L, and BMI 35 or more. The maximum is 6.

What Khorana score is high risk?

This page doesn't give a cutoff. It shows how the total is built.

Which cancers score 2 points?

Very high-risk sites: stomach and pancreas, per Magent's record.

Do low hemoglobin and an ESA both count?

They count once together, for 1 point.

Who developed the Khorana score?

Alok Khorana and colleagues, in a 2008 paper in Blood.