Correlation of microbiologic culture and fine-needle aspiration cytology: A 14-year experience at a single institution

Abstract

Background: Fine-needle aspiration (FNA) is an important tool for the diagnosis of infectious disease. FNA material should be appropriately submitted for cultures when indicated by preliminary findings. Correlation of cytologic diagnoses with culture results are important quality assurance tools. The current study reviewed 14 years of FNA-culture correlation.

Methods: FNA cytology-culture correlation records from the years 1996 through 2007 and 2010 through 2011 were retrieved from electronic databases compiled for histology and culture correlation. Correlation was limited to those cases for which material was submitted for culture from the FNA sample. Culture results were retrieved from the laboratory or hospital information system.

Results: Correlative data included 770 cases. Cytology, culture, or both were positive for microbes in 416 of 770 samples (54%), excluding cultured bacterial skin contaminants. Among the 204 bacteria cases, 93 (46%) were identified by cytology and culture, 92 (45%) were identified by culture only, and 19 (9%) were identified by cytology only. Among the 16 cases of Actinomycetales, 8 (50%) were identified by cytology and culture, 5 (31%) were identified by culture only, and 3 (19%) were identified by cytology only. Of the 129 cases of mycobacteria, 63 (49%) were identified by cytology and culture, 44 (34%) were identified by culture only, and 22 (17%) were identified by cytology only. Among the 67 cases of fungi, 34 (51%) were identified by cytology only, with 15 of these 34 cases being fungal hyphae; 25 cases (37%) were identified by cytology and culture, with a 100% concordance between the cytology diagnosis and culture result; and 8 cases (12%) were identified by culture only.

Conclusions: FNA cytology-culture correlation is a valuable tool with which to assess the efficacy and limitations of the direct diagnosis of infectious agents, and to identify types of infections that may be negative on culture but positive on cytology diagnosis.

Keywords: correlation; culture; cytology; microbiology; quality assurance.