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Table 1 Clinical signs of clubbing compared with Gold standard measure

From: Digital clubbing in tuberculosis – relationship to HIV infection, extent of disease and hypoalbuminemia

Clinical Sign "Gold standard" measurement Sensitivity
(%) (95%CI)
Specificity
% (95%CI)
Positive LR
(95%CI)
Negative LR
(95%CI)
p-Value
  Clubbing
(n = 60)
No Clubbing
(n = 140)
     
Nail bed fluctuation (n = 58) 43 15 71.7 (59.2, 81.5) 89.3 (83.1, 93.4%) 6.7 (4.1, 11.1) 0.3 (0.2, 0.5) < 0.001
Increased nail curvature (n = 53) 38 15 63.3 (50.7, 74.4%) 89.3 (89.3, 93.4%) 5.9 (3.5, 9.9) 0.4 (0.3, 0.6) < 0.001
Schamroth's sign (n = 41) 30 11 50.0 (37.7, 62.3%) 92.1 (86.5, 95.6%) 6.4 (3.4, 11.8) 0.5 (0.4, 0.7) < 0.001
Definite clubbing (n = 37) 31 06 51.7 (39.3, 63.8%) 95.7 (91.0, 98.0%) 12.1 (5.3, 27) 0.5 (0.4, 0.7) < 0.001
At least one sign (n = 76) 47 29 78.3 (66.4, 86.9%) 79.3 (71.8, 85.2%) 3.8 (2.7, 5.4) 0.3 (0.2, 0.4) < 0.001
Two or more signs (n = 54) 41 13 68.3 (55.8, 78.7%) 90.7 (84.8, 94.5%) 7.4 (4.3, 12.7) 0.3 (0.2, 0.5) < 0.001
No Clinical Sign (n = 123) 13 110 21.7 (13.1, 33.6%) 21.4 (15.4 – 28.9%) 0.3 (0.2, 0.5)   < 0.001
One Clinical Sign (n = 23) 06 17 10.0 (4.9, 20.1%) 87.9 (81.4, 92.3%) 0.8 (0.3, 2.0)   0.633
Two Clinical Signs (n = 18) 08 10 13.3 (6.9, 24.2%) 92.9 (87.4, 96.1%) 1.9 (0.8, 4.5)   0.130
Three Clinical Signs (n = 14) 12 02 20.0 (11.8, 31.8%) 98.6 (94.9, 99.6%) 14.0 (3.2, 61)   < 0.001
Four Clinical Signs (n = 22) 21 01 35.0 (24.2, 47.6%) 99.3 (96.1, 99.9%) 49.0 (6.7, 356)   < 0.001
  1. LR = Likelihood Ratio; CI = Confidence Interval