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Table 4 Diagnostic strategies to identify infection with Chlamydia trachomatis and/or Neisseria gonorrhoeae in 703 antenatal care attendees in Botswana.

From: Chlamydia and gonorrhoea in pregnant Batswana women: time to discard the syndromic approach?

  Positive on assessment Cervical infection Sensitivity Specificity LR+* LR- PPV NPV
  n (%) N (%)       
Symptoms and signs           
   VDS algorithm 104 (15) 11 (11) 0.16 0.85 1.12 (0.63–1.92) 0.98 0.11 0.91
   Symptoms alone: VD and/or LAP 155 (22) 14 (9) 0.21 0.78 0.94 (0.57–1.49) 1.02 0.09 0.90
   Signs alone: VD (excl. candidiasis) 227 (32) 30 (13) 0.45 0.69 1.45 (1.06–1.89) 0.78 0.13 0.92
Risk scores†, sensitivity minimum 0.7           
   Sociodemographic risk score 327 (47) 50 (15) 0.75 0.56 1.71 (1.42–1.99) 0.45 0.15 0.96
   Clinical risk score 372 (53) 54 (15) 0.81 0.50 1.61 (1.37–1.83) 0.39 0.15 0.96
   Microscopy risk score 273 (39) 51 (19) 0.76 0.65 2.18 (1.80–2.55) 0.37 0.19 0.96
Risk scores, sensitivity minimum 0.4           
   Sociodemographic risk score 156 (22) 29 (19) 0.43 0.80 2.17 (1.55–2.91) 0.71 0.19 0.93
   Clinical risk score 117 (17) 29 (25) 0.43 0.86 3.13 (2.20–4.30) 0.66 0.25 0.94
   Microscopy risk score 116 (17) 29 (25) 0.43 0.86 3.16 (2.22–4.34) 0.66 0.25 0.94
  1. LR+ = positive likelihood ratio; LR- = negative likelihood ratio; PPV = positive predictive value; NPV = negative predictive value; VDS = vaginal discharge syndrome;
  2. LAP = lower abdominal pain; VD = vaginal discharge
  3. * The positive likelihood ratios are calculated with 95% confidence interval.
  4. †Risk factors included in each risk score are described in Table 1