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Updated: Apr 16, 2026
Evaluation of a Point-of-Care Testing Analyzer for Measuring Peripheral Blood Leukocytes
Published on: March 22, 2022
Neutrophil CD64 level as a rapid and promising diagnostic tool for infectious diseases in elderly patients
Nozomi Otsuki1,2, Hiroshi Tsutani1,3, Toshihiro Matsui4
1Department of Internal Medicine, National Hospital Organization Awara Hospital, Awara, Japan.
Aim:
We examined the utility of the neutrophil CD64 level as a rapid and sensitive diagnostic marker for infections in febrile aged patients.
Methods:
The expression level of CD64 per neutrophil was quantitatively measured with flow cytometry using a QuantiBrite kit in samples from febrile (aged >65 years) patients. Information about the presence or absence of infectious disease was retrospectively obtained from each patient's medical record in which attending physicians were obliged to write down a tentative diagnosis after resolution of manifestations.
Results:
With receiver operating characteristic curve evaluation using the results, a CD64 level >2000 molecules per neutrophil was sensitive and specific for detecting infection. Among 102 patients suspected of having infection, 72 patients were diagnosed with infectious diseases, and 30 patients had non-infectious diseases. The sensitivity and specificity of determination of the neutrophil CD64 level were 88% and 63%, respectively. However, considering the high frequency of infections in elderly patients (71% in the present study), the post-test probability reached as high as 93%. The positive likelihood ratio was 2.4, and the negative likelihood ratio was 0.2.
Conclusions:
Considering the frequency of infectious diseases in elderly patients, determination of the neutrophil CD64 level helps detect infectious diseases.
