Table 3

Algorithm approaches to diagnosis of alcohol problems in primary care in hypothetical 1000 attendees

Sensitivity (95% CI)Specificity (95% CI)PPV (95% CI)NPV (95% CI)Overall accuracy (95% CI)Positive clinical utility index (95% CI)Negative clinical utility index (95% CI)Questions asked per 100 attendees
Combined algorithms
SQ then AUDIT0.337 (0.272 to 0.403)0.989 (0.981 to 0.996)0.886 (0.810 to 0.955)0.856 (0.834 to 879)0.858 (0.837 to 0.880)0.298 (0.292 to 0.303)
‘v poor’		0.847 (0.847 to 0.847)
‘excellent’		311
2QQ then AUDIT0.540 (0.471to 0.609)0.983 (0.973 to 0.992)0.885 (0.829 to 0.942)0.895 (0.875 to 0.915)0.894 (0.875 to 0.913)0.478 (0.474 to 0.482)
‘poor’		0.880 (0.879 to 0.880)
‘excellent’		536
SQ then CAGE0.387 (0.319 to 0.455)0.988 (0.980 to 0.995)0.886 (0.819 to 0.952)0.866 (0.844 to 0.888)0.867 (0.846 to 0.888)0.343 (0.337 to 0.348)
‘v poor’		0.855 (0.885 to 0.885)
‘excellent’		184
2QQ then CAGE0.620 (0.553 to 0.687)0.981 (0.972 to 0.991)0.892 (0.841 to 0.944)0.912 (0.893 to 0.931)0.909 (0.891 to 0.926)0.553 (0.549 to 0557)
‘fair’		0.895 (0.894 to 0.895)
‘excellent’		334
Single applications
CAGE Single application0.615 (0.548 to 0.682)0.915 (0.896 to 0.934)0.644 (0.576 to 0.712)0.905 (0.885 to 0.925)0.855 (0.833 to 0.876)0.396 (0.392 to 0.400)
‘poor’		0.828 (0.828 to 0.828)
‘excellent’		400
AUDIT Single application0.71 (0.647 to 0.773)0.91 (0.890 to 0.930)0.664 (0.600 to0.727)0.926 (0.908 to 0.944)0.870 (to 0.849 to 0.890)0.471 (0.468 to 0.475)
‘poor’		0.843 (0.842 to 0.843)
‘excellent’		1000
SQ Single application0.545 (0.476 to 0.614)0.873 (0.849 to 0.896)0.517 (0.449 to 0.584)0.885 (0.862 to 0.907)0.807 (0.782 to 0.831)0.282 (0.278 to 0.285)
‘v poor’		0.772 (0.771 to 0.772)
‘excellent’		100
2QQ Single application0.87 (0.823 to 0.917)0.798 (0.770 to 0.825)0.518 (0.464 to 0.571)0.961 (0.946 to 0.976)0.812 (0.787 to 0.836)0.451 (0.448 to 0.453)
‘poor’		0.766 (0.766 to 0.767)
‘excellent’		200

  • Table shows hierarchical screening algorithms applied to 1000 hypothetical primary care attendees, of whom 200 have alcohol problems. Calculations from www.clinicalutlity.co.uk. 2QQ = two questions. NPV = negative predictive value. PPV = positive predictive value. SQ = single question.