Vienna CATS score (CATS/MICA model)

Q: What is the CATS/MICA score?

A Vienna-developed nomogram that combines tumour-site category (low/intermediate, high, very high) with D-dimer to give a 6-month VTE risk in percent.

Q: How is it different from the Khorana score?

It needs only two variables, uses D-dimer as a continuous value, reclassifies colorectal cancer as high-risk and gives a percentage instead of a points category.

Q: What risk threshold suggests thromboprophylaxis?

The authors propose considering prophylaxis at a predicted 6-month risk of 10–15 % and regard it as justified at ≥ 15 %, always weighed against bleeding risk.

6-month risk of cancer-associated VTE from tumour site and D-dimer

Vienna CATS cohort, Medical University of Vienna
Validated in MICA (Austria/Germany)

Sources last checked: 2026-10-13

Vienna CATS score (CATS/MICA model)

6-month risk of cancer-associated VTE from tumour site and D-dimer

Tumour-site risk category

D-dimer (µg/mL FEU)µg/mL = mg/L FEU. 500 µg/L = 0.5 µg/mL. The nomogram covers 0.1–32 µg/mL.

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Developed for ambulatory patients with solid cancers (and lymphoma) in the CATS cohort; primary brain tumours, myeloma and other haematological cancers were excluded. D-dimer assays differed between cohorts (STA-Liatest, Innovance) — values from other assays may not be interchangeable. Discrimination is moderate (C-index 0.66–0.68).

Source: Pabinger I et al. A clinical prediction model for cancer-associated venous thromboembolism: a development and validation study in two independent prospective cohorts. Lancet Haematol 2018;5(7):e289-e298.Open

Interpretation

< 10 % — lower predicted risk	Predicted 6-month VTE risk below the 10 % threshold examined by the authors; routine primary prophylaxis not supported by the model.
10–15 % — elevated risk	The authors suggest primary thromboprophylaxis may be considered in this range, weighing bleeding risk.
≥ 15 % — high risk	The authors consider thromboprophylaxis justified at a predicted 6-month risk of 15 % or more, unless bleeding risk prohibits it.

What is the Vienna CATS score (CATS/MICA model)?

The Vienna CATS score (CATS/MICA model) estimates the 6-month risk of cancer-associated VTE from just two inputs: a tumour-site risk category and the D-dimer level. Pabinger and colleagues developed it in the prospective Vienna Cancer and Thrombosis Study (CATS) and validated it in the MICA cohort (Lancet Haematol 2018). It needs fewer variables than the Khorana score and gives a continuous risk estimate.

When to use it

Ambulatory patients with solid tumours or lymphoma, to estimate 6-month VTE risk.
When a D-dimer value is available and a continuous risk estimate is preferred over a points score.
Shared decision-making on primary thromboprophylaxis.

When not to use it

Primary brain tumours, myeloma and other haematological malignancies (excluded).
Patients already anticoagulated or with acute VTE.
Inpatients, where acute illness raises D-dimer for other reasons.

How it is calculated

6-month VTE risk (%) = 100 × [1 − (1 − 0.02137053)^exp(0.6709158 × site + 0.2793001 × log₂(D-dimer + 1))] site: 0 = low/intermediate, 1 = high, 2 = very high; D-dimer in µg/mL FEU

Clinical pearls and limitations

Developed for ambulatory patients with solid cancers (and lymphoma) in the CATS cohort; primary brain tumours, myeloma and other haematological cancers were excluded. D-dimer assays differed between cohorts (STA-Liatest, Innovance) — values from other assays may not be interchangeable. Discrimination is moderate (C-index 0.66–0.68).
Each step up in tumour-site category multiplies the hazard by about 1.96; each doubling of D-dimer by about 1.32.
D-dimer is entered in µg/mL (= mg/L) FEU; 0.5 µg/mL equals 500 µg/L.
Colorectal cancer is 'high' risk here, unlike in the Khorana score.
The authors consider prophylaxis justified at a predicted 6-month risk of ≥ 15 % and possibly from 10 %.

Frequently asked questions

What is the CATS/MICA score?

A Vienna-developed nomogram that combines tumour-site category (low/intermediate, high, very high) with D-dimer to give a 6-month VTE risk in percent.

How is it different from the Khorana score?

It needs only two variables, uses D-dimer as a continuous value, reclassifies colorectal cancer as high-risk and gives a percentage instead of a points category.

What risk threshold suggests thromboprophylaxis?

The authors propose considering prophylaxis at a predicted 6-month risk of 10–15 % and regard it as justified at ≥ 15 %, always weighed against bleeding risk.

Evidence and guidelines

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