NYMC Faculty Publications

Culture and Other Direct Detection Methods to Diagnose Human Granulocytic Anaplasmosis

Author Type(s)

Faculty

DOI

10.1093/ajcp/aqae126

Journal Title

American Journal of Clinical Pathology

First Page

313

Last Page

319

Document Type

Article

Publication Date

2-1-2025

Second Department

Medicine

Keywords

Anaplasma phagocytophilum, anaplasmosis, blood culture, diagnosis, human granulocytic anaplasmosis, polymerase chain reaction, smear

Disciplines

Medicine and Health Sciences

Abstract

Objectives: We sought to assess the performance of 3 laboratory tests on blood specimens for direct detection of Anaplasma phagocytophilum, the cause of human granulocytic anaplasmosis (HGA), in patients tested at a single medical institution in New York State. Methods: Direct tests included microscopic blood smear examination for intragranulocytic inclusions, polymerase chain reaction (PCR), and culture using the HL-60 cell line. The HGA cases testing positive by only 1 direct test were not included, unless HGA was confirmed by acute or convalescent serology using an indirect immunofluorescent assay. Results: From 1997 to 2009, 71 patients with HGA were diagnosed by at least 1 of the 3 direct test methods. For the subgroup of 55 patients who were tested using all 3 methods, culture was positive for 90.9% (50/55) vs 81.8% (45/55) for PCR vs 63.6% (35/55) for blood smear (P =.002). Most cultures (79.3%) were detected as positive within 1 week of incubation. Conclusions: Although using culture to detect A phagocytophilum is likely not amenable for implementation in most hospital laboratories, in our experience, culture had the highest yield among the direct tests evaluated.

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