Frost K, Schick A, Mount R. A retrospective analysis of the concordance of in-house fungal culture and a commercial quantitative PCR from 16 dermatology referral practices across the USA (2018-2019).
Vet Dermatol 2022;
33:392-397. [PMID:
35661448 DOI:
10.1111/vde.13085]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/20/2022] [Accepted: 03/16/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND
Commercial quantitative (q)PCR and fungal culture can be used concurrently or individually to test for dermatophytosis with a reported high sensitivity and specificity.
HYPOTHESIS/OBJECTIVES
The aims of this retrospective study were: (i) to evaluate the concordance of a commercial qPCR with in-house fungal culture for the initial diagnosis of dermatophytosis and for monitoring for mycological cure during treatment in dermatology private practice; and (ii) determine the sensitivity and specificity of qPCR overall, (iii) for initial diagnosis and (iv) for treatment monitoring in dogs and cats.
ANIMALS
Four-hundred and twenty-seven client-owned dogs and 188 client-owned cats.
MATERIALS AND METHODS
Retrospective evaluation of electronic medical records from 615 client-owned dogs and cats presented to 16 dermatology referral practices across the USA from 2018 to 2019. Concordance of qPCR with in-house fungal culture and sensitivity and specificity were determined from 667 paired samples.
RESULTS
qPCR agreed with in-house fungal culture in 63 of 85 positive tests and 571 of 582 negative tests, with an overall sensitivity and specificity of 74.1% [95% confidence interval (CI) 63.5-83.0] and 98.1% (95%CI 96.6-99.0), respectively. qPCR sensitivity and specificity for the initial diagnosis of dermatophytosis and for treatment monitoring were 72.4% (95%CI 59.1-83.3) and 98.7% (95%CI 97.3-99.5), and 77.8% (95%CI 57.7-91.4) and 92.0% (95%CI 80.1-97.8), respectively.
CONCLUSIONS AND CLINICAL RELEVANCE
Compared to in-house fungal culture, qPCR was less sensitive and more specific than reported previously. These findings suggest that a diagnosis of dermatophytosis and determining mycological cure should continue to be based on a combination of complementary diagnostic tests.
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