A prospective study to evaluate a microfluidic flow cytometry–based analyzer in waived settings.

Author: Jane F. Emerson, MD, PhD; Hao Wang, MD; Imran N. Siddiqi, MD, PhD

Objectives: A microfluidic flow cytometer–based point-of-care (POC) analyzer was validated against an in-laboratory hematology analyzer (Sysmex XN Automated Hematology System). Concordance on a full complete blood cell count (CBC) with 5-part differential, as performed by operators with no prior clinical laboratory experience, was evaluated. 

Methods: We prospectively collected 376 venous blood specimens (376) from individuals with self-reported medical conditions and from apparently healthy individuals. Forty-six additional remnant specimens were acquired to ensure coverage of analytic measuring ranges. Parallel testing was performed, with up to 7 hours between testing on the POC and Sysmex XN analyzers. 

Results: Regression analysis resulted in r values of 0.998 to 0.932 for all parameters of a 5-part differential CBC other than basophils (0.709). The mean percentage bias from the reference method, inclusive of the upper and lower reporting limits, was less than 2% for parameters other than lymphocytes (–6.4%), monocytes (25.9%), eosinophils (12.2%), and basophils (–15%). Overall agreement on abnormal flagging was 93.3%. 

Conclusions: The Cito CBC microflow cytometer (CytoChip Inc) provides a CBC with a 5-part differential with accuracy, precision, and abnormal flagging equivalent to a moderate-complexity hematology analyzer. It has the key features required of a POC device that can be operated in a waived setting: minimum space requirements, rapid results, single-action measurement (no sample processing or dilution), ease of use, and minimal blood volume.

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