Laboratory testing:
(1) erythrocyte sedimentation rate (ESR): mm in first hour
(2) acid alpha-1 glycoprotein in mg/dL: reference range 55-140 mg/dL
(3) alpha-2 globulin in g/dL
prognostic index =
= (-3.5) + (0.03 * (ESR)) + (0.013 * (acid alpha-1 glycoprotein in mg/dL)) + (2 * (alpha-2 globulin in g/dL))
Interpretation:
• minimum value: close to -2
• maximum value: close to +5
• A value > 0.35 was used to separate patients who relapsed within 18 months from those who did not.
Performance of equation and discriminant value
• sensitivity 71%, specificity 100%
• accuracy 88% and positive predictive value of 100%
Limitations:
• Performance of the index will depend on how well the user's chemical analyses match those of the authors, especially for the acid alpha-1 glycoprotein. The ESR and alpha-2 globulin should be fairly comparable between institutions.
