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Table 4 Sensitivity and specificity estimates for diagnosis of S. pneumoniae, N. meningitidis, or H. influenzae meningitis

From: Accuracy of real-time PCR, Gram stain and culture for Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae meningitis diagnosis

  Culture Standard CRSa LCA Modelb
Sens (%, 95CI) Spec (%, 95CI) Sens (%, 95CI) Spec (%, 95CI) Sens (%, 95CI) Spec (%, 95CI)
S. pneumoniae, N. meningitidis, or H. influenzae     
All patients, n=451 Culture na na na na 81.3 (73.2-89.3) 99.7 (99.1-100.0)
   Gram stain 97.5 (91.3-99.7) 94.1 (91.2-96.3) na na 98.2 (95.2-100.0) 98.7 (97.3-100.0)
   RT-PCR 95.0 (87.7-98.6) 90.0 (86.5-92.9) 91.2 (83.9-95.9) 94.3 (91.3-96.5) 95.7 (91.2-100.0) 94.3 (91.9-96.8)
Antibiotic negative, n=341 Culture na na na na 85.7 (74.4-96.9) 100.0 (99.8-100.0)
   Gram stain 100.0 (89.7-100.0) 97.4 (94.9-98.9) na na 98.7 (94.9-100.0) 99.0 (97.9-100.0)
   RT-PCR 97.1 (84.7-99.9) 96.1 (93.3-98.0) 90.5 (77.4-97.3) 97.7 (95.2-99.1) 95.8 (89.1-100.0) 97.7 (95.9-99.4)
Antibiotic positive, n=98 Culture na na na na 78.2 (66.4-89.9) 97.1 (91.9-100.0)
   Gram stain 97.7 (88.0-99.9) 74.1 (60.4-85.0) na na 99.5 (97.3-100.0) 94.0 (84.1-100.0)
   RT-PCR 93.2 (81.3-98.6) 55.6 (41.4-69.1) 91.4 (81.0-97.1) 70.0 (53.5-83.4) 95.3 (89.0-100.0) 70.2 (56.2-84.2)
S. pneumoniae only       
All patients, n=451 Culture na na na na 85.3 (74.8-95.9) 100.0 (99.9-100.0)
   Gram stain 97.5 (86.8-99.9) 97.6 (95.6-98.8) na na 96.4 (90.6-100.0) 99.0 (98.1-100.0)
   RT-PCR 97.5 (86.8-99.9) 97.1 (95.0-98.5) 90.0 (78.2-96.7) 98.5 (96.8-99.5) 96.4 (90.6-100.0) 98.6 (97.4-99.7)
N. meningitidis only       
All patients, n=451 Culture na na na na 77.9 (65.4-90.4) 99.8 (99.3-100.0)
   Gram stain 97.2 (85.5-99.9) 97.4 (95.3-98.7) na na 98.7 (94.8-100.0) 99.6 (98.9-100.0)
   RT-PCR 94.4 (81.3-99.3) 94.5 (91.8-96.5) 91.5 (79.6-97.6) 96.5 (94.3-98.1) 95.9 (89.3-100.0) 96.6 (94.8-98.3)
  1. Performance parameters for the various tests are estimated using a CSF culture reference standard, composite reference standard (CRS), and latent class analysis (LCA) modeling with stratification by antimicrobial detection disk bioassay results.
  2. Abbreviations: CRS, composite reference standard; LCA, latent class analysis; na, not applicable; 95% CI, 95% exact binomial confidence interval for culture reference standard and CRS parameters, or parameter estimate +/− 1.96 * standard error for LCA models.
  3. aComposite reference standard defined as positive if CSF culture or Gram stain positive for S. pneumoniae, N. meningitidis, or H. influenzae.
  4. bFor LCA model of all patients, disease prevalence was 21.5% (95% CI 17.7-25.4). For the model of antibiotic assay-negative patients, disease prevalence was 11.6% (95CI 8.2-15.0). For the model of antibiotic assay-positive patients, disease prevalence was 55.8% (96CI 45.4-66.1). For the model of S. pneumoniae diagnosis, disease prevelance was 10.4% (95CI 7.5-13.2). For the model of N. meningitidis diagnosis, disease prevalence was 10.0% (95CI 7.2-12.7). Bootstrap p for all models >0.1.