Meningitis: PCR of blood may help diagnosis.

Clinical bottom line (level 2b)

  1. Nearly two-thirds of patients with suspected meningococcal disease had it.
  2. Patients with a positive PCR result using buffy coat had meningococcal disease (LR 8 ), and those with a negative result do not had it (LR 8 ).
  3. Patients with a positive PCR result using serum had meningococcal disease (LR 8 ), and those with a negative result were less likely to have it (LR 0.15).
Newcombe et al: Journal of Clinical Microbiology 1996; 34 (7): 1637-1640
Expires November 2003

The study

Setting: 4 cities, UK

40 patients (aged ?, ?% male) proven meningicoccal septicaemia with blood culture, confirmed meningicoccal disease by positive CSF, but blood culture negative or blood not taken and control patients with other types of meningitis or other conditions

Independent ?blinded reference standard, applied in all patients from a non-consecutive appropriate spectrum.
Reference standard:
  • confirmed diagnosis of meningicoccal disease (culture and clinical course)
Diagnostic test: PCR of peripheral blood using the DIG-PCR enzyme-linked immunosorbent assay. DNA was purified from 50 µ L of blood buffy coat or serum sample. 'Positive' result not clearly decided a priori.

The evidence


diagnostic test meningicoccal disease no meningicoccal disease LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
PCR with DNA from buffy coat 25 0 -
(23.3 to infinity) 		100% -
(41.7 to infinity) 		0.00%
PCR with DNA from serum sample 22 0 -
(23.3 to infinity) 		100% 0.15
(0.06 to 0.38) 		22.0%
total 25 14

Comments

  1. The PCR was done as a research test after overnight freezing, and the technique requires 8 hrs. vs. 12-36 hrs for routine culture - uncertain clincal relevance

Citation

  1. Newcombe J, Cartwright K, Palmer WH, et al: PCR of peripheral blood for diagnosis of meningococcal disease. Journal of Clinical Microbiology 1996; 34 (7): 1637-1640
Search Terms: meningitis in Cochrane and Best Evidence; meningitis and diagnosis in Medline
Contributor: Clare Wotton and Musab Hyatli, November 1999
Reviewer: Donald E Stanley

Clinical Question.
Patient suspected meningicoccal disease
Intervention or Exposure PCR of peripheral blood
Comparison standard haematological tests
Outcome diagnosis