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Sputum gram's stain in community-acquired pneumococcal pneumonia. A meta-analysis

W W Reed1, G S Byrd, R H Gates

  • 1Department of Medicine, Fitzsimons Army Medical Center, Aurora, Colorado, USA.

The Western Journal of Medicine
|October 1, 1996
PubMed

Insights

The sputum Gram's stain for diagnosing community-acquired pneumococcal pneumonia shows variable accuracy. This meta-analysis found its sensitivity and specificity differ significantly, potentially leading to misleading results.

Area of Science:

  • Microbiology
  • Pulmonary Medicine
  • Diagnostic Accuracy Studies

Background:

  • The diagnostic utility of sputum Gram's stain in community-acquired pneumonia remains debated.
  • Accurate and rapid diagnostic methods are crucial for effective treatment of bacterial pneumonia.

Purpose of the Study:

  • To systematically evaluate the sensitivity and specificity of sputum Gram's stain for diagnosing pneumococcal pneumonia acquired in the community.
  • To identify factors influencing the test's performance characteristics.

Main Methods:

  • A meta-analysis was conducted using articles identified via MEDLINE search (1966-1993) and bibliography review.
  • Twelve studies with 17 test characteristics were analyzed, assessing reference standards, blinding, interpreter variability, and antibiotic use.
  • Quality grading was performed by three blinded reviewers.

Main Results:

  • Sensitivity of sputum Gram's stain ranged from 15% to 100%, and specificity from 11% to 100%.
  • Significant variability in test characteristics was observed across studies.
  • Performance appeared partly related to the stain interpreter.

Conclusions:

  • Sputum Gram's stain results in community-acquired pneumonia can be misleading due to substantial variations in sensitivity and specificity.
  • Clinicians should be well-trained and use a precise definition for a positive test when employing this diagnostic method.

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