Context.—
In the XN series of hematology analyzers (Sysmex, Kobe, Japan), the probability of the presence of abnormal cells is indicated by flags based on Q values.
Objective.—
To evaluate the Q value performance of the Sysmex XN-20 modular analyzer.
Design.—
The interinstrumental concordance, intrainstrumental precision, and diagnostic accuracy of Q values, with tested flags of “blasts/abnormal lymphocytes,” “atypical lymphocytes,” and “blasts,” were investigated.
Results.—
Absolute concordance rates in flagging between 2 analyzers ranged from 69.8% to 80.8%, and κ values ranged from 0.43 to 0.61. In samples with absolute related cell counts lower than 100/μL, the values ranged from 0.31 to 0.52. For intrainstrumental precision, standard deviations ranged from 4.8 to 23.9 for the blasts/abnormal lymphocytes, from 18.7 to 59.1 for the blasts, and from 11.0 to 23.0 for the atypical lymphocytes. Using a default Q value cutoff, diagnostic accuracy values based on the area under the curve, sensitivity, and specificity were, respectively, 0.910, 90.9%, and 72.2% for blasts/abnormal lymphocytes; 0.927, 84.9%, and 89.8% for blasts; and 0.865, 74.4%, and 84.9% for atypical lymphocytes. The diagnostic accuracy of Q values was much lower in samples with absolute related cell counts lower than 100/μL than in those 100/μL or higher.
Conclusions.—
Q values of the Sysmex XN-20 analyzer were found to be imprecise and irreproducible, especially with samples containing a small number of pathologic cells. Adjustments in the Q value threshold may help in the detection of these cells.
CORRELATION OF MONOCYTE COUNT, MLR AND NLCR WITH PRESEPSIN LEVEL IN SIRS (Hubungan Jumlah Monosit, MLR dan NLCR dengan Kadar Presepsin pada SIRS)
