The diagnostic accuracy of Gram stain on formalin-fixed paraffin-embedded sections of skin tissue in the diagnosis of bacterial skin infection.
Gram stain
diagnostic accuracy
skin and soft tissue infection
skin biopsy
Journal
Journal of cutaneous pathology
ISSN: 1600-0560
Titre abrégé: J Cutan Pathol
Pays: United States
ID NLM: 0425124
Informations de publication
Date de publication:
23 Nov 2023
23 Nov 2023
Historique:
revised:
31
10
2023
received:
25
07
2023
accepted:
11
11
2023
medline:
24
11
2023
pubmed:
24
11
2023
entrez:
24
11
2023
Statut:
aheadofprint
Résumé
To evaluate the sensitivity, specificity, and likelihood ratios of Gram stain on formalin-fixed, paraffin-embedded (GS-FFPE) sections of skin in diagnosing bacterial skin infection. We reviewed a retrospective series of skin specimens reported at our institution wherein histopathological assessment included Gram stain and fresh tissue was concurrently submitted for microscopy and culture. The clinicopathological correlation was the reference standard, whereby the presence of infection was deduced from the final diagnosis in each patient's case notes. Our sample included 168 cases (105 positive for infection). GS-FFPE showed a sensitivity of 0.43 (95% confidence interval 0.29, 0.57), a specificity of 0.98 (0.95, 1.01), a positive likelihood ratio of 21.50 (19.76, 23.24), and a negative likelihood ratio of 0.58 (0.41, 0.75). GS-FFPE has poor sensitivity, and a negative result should not be used as evidence to exclude infection. In contrast, it has excellent specificity and, unless the pretest probability of infection is very low, a positive result would make infection much more likely. The value of the GS-FFPE lies in cases where sterile tissue was not submitted for microbiological studies, or sterile tissue culture was negative, and there is at least a low-to-moderate pretest probability of infection.
Sections du résumé
BACKGROUND AND OBJECTIVE
OBJECTIVE
To evaluate the sensitivity, specificity, and likelihood ratios of Gram stain on formalin-fixed, paraffin-embedded (GS-FFPE) sections of skin in diagnosing bacterial skin infection.
METHODS
METHODS
We reviewed a retrospective series of skin specimens reported at our institution wherein histopathological assessment included Gram stain and fresh tissue was concurrently submitted for microscopy and culture. The clinicopathological correlation was the reference standard, whereby the presence of infection was deduced from the final diagnosis in each patient's case notes.
RESULTS
RESULTS
Our sample included 168 cases (105 positive for infection). GS-FFPE showed a sensitivity of 0.43 (95% confidence interval 0.29, 0.57), a specificity of 0.98 (0.95, 1.01), a positive likelihood ratio of 21.50 (19.76, 23.24), and a negative likelihood ratio of 0.58 (0.41, 0.75).
CONCLUSIONS
CONCLUSIONS
GS-FFPE has poor sensitivity, and a negative result should not be used as evidence to exclude infection. In contrast, it has excellent specificity and, unless the pretest probability of infection is very low, a positive result would make infection much more likely. The value of the GS-FFPE lies in cases where sterile tissue was not submitted for microbiological studies, or sterile tissue culture was negative, and there is at least a low-to-moderate pretest probability of infection.
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Informations de copyright
© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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