Discriminant Formula of Clayton et al for Prediction of Post-Operative Deep Vein Thrombosis

Description

Clayton et al developed a discriminant score for identifying patients at high risk for deep vein thrombosis prior to surgery. Patients at high risk may benefit from closer monitoring and prophylactic measures to reduce the thrombotic tendency. The authors are from the University of Leeds in England.

Parameters:

(1) euglobin clot lysis time in minutes (a measure of plasminogen activator. The fibrinolytic activity is inversely related to the clot lysis time.)

(2) concentration of fibrin-related antigen in mg/L (related to fibrin split products)

(3) age in years

(4) percentage overweight for height

(5) presence of varicose veins (1 point if present, 0 points if absent)

percentage overweight for height =

= ((weight in kilograms) – (ideal weight for height)) / (ideal weight for height) * 100%

where:

• The ideal body weight can be calculated based on the equations in Chapter 2.

discriminant score =

= (0.009 * (euglobin clot lysis time)) + (0.22 * (fibrin related antigen)) + (0.085 * (age in years)) + (0.043 * (percentage overweight)) + (2.19 * (points for varicose veins)) – 11.3

Interpretation:

Score	Risk of Thrombosis
> 1	high
-1 to +1	moderate
> -3 to < -1	low
<= -3	very low

from diagram page 911, Clayton (1976)

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Description

Specialty

ICD-10