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Table 2 Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, and overall accuracy for the diagnostic algorithm and the summary score (≥10) of the PHQ-9

From: Utility and limitations of PHQ-9 in a clinic specializing in psychiatric care

  Diagnosis of current major depressive episode (MDE) Diagnosis of MDE with major depressive disorder
  Diagnostic algorithm of PHQ-9 Summary score (≥10) of the PHQ-9 Diagnostic algorithm of PHQ-9 Summary score (≥10) of the PHQ-9
True positive, n (%) 39 (25) 47 (31) 32 (21) 38 (25)
False positive, n (%) 34 (22) 52 (34) 41 (27) 61 (40)
False negative, n (%) 11 (7) 3 (2) 9 (6) 3 (2)
True negative, n (%) 69 (45) 51 (33) 71 (46) 51 (33)
Sensitivity (95%CI) 0.78 (0.64–0.88) 0.94 (0.84–0.99) 0.78 (0.62–0.89) 0.93 (0.80–0.98)
Specificity (95%CI) 0.67 (0.57–0.76) 0.50 (0.40–0.60) 0.63 (0.54–0.72) 0.46 (0.36–0.55)
Positive predictive value (95%CI) 0.53 (0.41–0.65) 0.47 (0.37–0.58) 0.44 (0.32–0.56) 0.38 (0.29–0.49)
Negative predictive value (95%CI) 0.86 (0.77–0.93) 0.94 (0.85–0.99) 0.89 (0.80–0.95) 0.94 (0.85–0.99)
Positive likelihood ratio (95%CI) 2.36 (1.76–2.99) 1.86 (1.56–2.02) 2.13 (1.59–2.63) 1.70 (1.41–1.85)
Negative likelihood ratio (95%CI) 0.33 (0.19–0.53) 0.12 (0.04–0.33) 0.35 (0.19–0.59) 0.16 (0.05–0.43)
Overall accuracy (95%CI) 0.71 (0.64–0.76) 0.64 (0.58–0.67) 0.67 (0.61–0.72) 0.58 (0.53–0.61)
  1. 95%CI, 95% confidence intervals; MDE, major depressive episode.