Meningitis: latex agglutination tests may help identify the infecting organism

Clinical bottom line (level 4)

  1. One in six children with bacterial septicaemia or meningitis were infected with Neisseria meningitidis, Streptococcus pneumoniae or Haemophilus influenzae.
  2. Latex agglutination tests may help diagnose (LR+29) and rule out these infections (LR-0.0) .
Williams and Hart: Journal of Clinical Pathology 1988; 41: 691-693
Expires November 2003

The study

Setting: acute hospital, UK

- patients (aged ?, ?% male) children with suspected bacterial septicaemia or meningitis; or severely ill with a fever of unknown origin providing 272 blood culture sets and 85 CSF samples

Independent unblinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:
  • blood or CSF culture
Diagnostic test: latex agglutination tests for N. meningitidis, H. influenzae b and S. pneumoniae

The evidence

pre-test probability of infection with pneumococcus, meningococcus or Hib: 18%, (95% CI: 14% to 22%)

diagnostic test Hib, meningococcal or pneumococcal pneumonia other infection LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
latex agglutination 64 10 29
(16 to 54) 		86% 0.0
(0.0 to 0.047) 		0.0%
total

Comments

  1. We don't know how the count was done: if on specimens or patients; thus the count on specimens, if done, would give a false sense of sensitivity especially if duplicate positive specimens were not excluded.
  2. This test is not routinely offered in USA because of its lack of sensitivity and problems with cross reaction. The sensitivity in this study has not been confirmed.
  3. Routine vaccination against H. influenzae has been introduced in the UK since this study - consequently the pre-test probability now is lower.

Citation

  1. Williams G, and Hart CA: Rapid identification of bacterial antigen in blood cultures and cerebrospinal fluid. Journal of Clinical Pathology 1988; 41: 691-693
Contributor: Chris Ball and Clare Wotton, November 1999
Reviewer: Donald E Stanley

Clinical Question.
Patient children with suspected bacterial septicaemia or meninginitis
Intervention or Exposure latex agglutination
Outcome meningococcal, pneumococcal or H. influenzae infection