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Errors in interpretation of Gram stains from positive blood cultures
1Department of Pathology, Division of Infectious Disease, University of Florida, Gainesville, FL 32610, USA.
Abstract:
We reviewed major errors in Gram stain reports from positive blood cultures to identify patterns and potential clinical impact. During a 23-month period, blood cultures were misread for 57 (0.7%) of 8,253 patients. Of 5,885 read as gram-positive cocci, 6 (0.1%) had only gram-negative organisms by culture, 3 of which were Acinetobacter species Of 1,959 read as gram-negative bacilli, 25 (1.3%) had only gram-positive organisms by culture. Of these, 9 were Bacillus and 2 were Clostridium species. Nonrecognition of mixed Gram stains accounted for 28 errors that most often were associated with a reading of gram-positive cocci. In 4 cases, there were delays of 14 hours to 3 days in starting appropriate antibiotic treatment; 2 deaths occurred, although the erroneous Gram stain report probably was not contributory. Pathologists and laboratory personnel need to be aware of these types of misinterpretations and the potential effects on patient outcome.
Insights
Major errors in Gram stain reports from blood cultures occurred in 0.7% of patients. Misinterpretations of Gram stains can lead to delayed antibiotic treatment, highlighting the need for improved laboratory accuracy.
Area of Science:
- Medical Microbiology
- Clinical Pathology
Background:
- Gram stain is a critical initial diagnostic tool for bacterial infections.
- Accurate Gram stain interpretation of blood cultures is essential for timely patient management.
Purpose of the Study:
- To identify patterns and assess the clinical impact of major errors in Gram stain reports from positive blood cultures.
Main Methods:
- A retrospective review of Gram stain reports from positive blood cultures over a 23-month period.
- Analysis of misinterpretations, including false-positive and false-negative results, and nonrecognition of mixed organisms.
Main Results:
- 57 (0.7%) of 8,253 patients had misread Gram stains.
- Errors included misidentification of Gram-positive cocci as Gram-negative bacilli and vice versa.
- Nonrecognition of mixed Gram stains accounted for 28 errors, often associated with Gram-positive cocci reports.
Conclusions:
- Significant errors in Gram stain interpretation from blood cultures occur.
- These errors can potentially lead to delayed appropriate antibiotic therapy.
- Enhanced awareness and improved laboratory practices are crucial to minimize misinterpretations and optimize patient outcomes.
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