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Histologic parameters predictive of mycobacterial infection
Y W Tang1, G W Procop, X Zheng
1Department of Laboratory Medicine and Pathology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
American Journal of Clinical Pathology
|March 12, 1998
Summary
Auramine-rhodamine (AR) staining and mycobacterial cultures are most effective for detecting acid-fast bacilli (AFB) in necrotizing granulomas. Specimens with other diagnoses are inappropriate for AFB testing.
Area of Science:
- Medical Microbiology
- Anatomic Pathology
Background:
- Mycobacteria detection in tissue is crucial for diagnosing infections.
- Auramine-rhodamine (AR) staining is a sensitive method for identifying acid-fast bacilli (AFB) in tissue sections.
Purpose of the Study:
- To evaluate the diagnostic yield of AR staining and mycobacterial cultures in various tissue specimen types.
- To identify inappropriate biopsy specimens for AFB testing.
Main Methods:
- Retrospective review of 85 AR-positive and 275 AR-negative biopsy specimens.
- Analysis of pathologic diagnoses and corresponding mycobacterial culture results.
Main Results:
- AR staining positivity was highest in necrotizing granulomas (47.7%), followed by non-necrotizing (17.7%), poorly formed granulomas (16.1%), and acute inflammation (15.6%).
- Mycobacteria were cultured from necrotizing granulomas (38.2%), non-necrotizing granulomas (32.4%), poorly formed granulomas (30.0%), and acute inflammation (15.8%).
- Specimens with fibrotic, hyalinized, or chronically inflamed tissues, or malignancy, were consistently negative for AFB and cultures.
Conclusions:
- Biopsy specimens with diagnoses other than granulomatous inflammation or acute inflammation are inappropriate for mycobacterial culture or AR staining.
- Targeting AFB testing to specific histopathologic findings can improve diagnostic efficiency.