Use of the Sysmex XT-4000i hematology analyzer in the differentiation of cerebrospinal fluid cells in children

Abstract

Background: Routine analysis of pleocytosis and cellular composition of cerebrospinal fluid (CSF) is carried out with a phase-contrast microscope. The use of hematological analyzers seems to be an alternative to the manual method. The aim of the study was to assess the usefulness of the automated technique for counting and differentiating CSF cells in children.

Methods: The study group consisted of 59 children (28 girls and 31 boys) aged from 4 to 17 years suffering from viral and bacterial meningitis. Children were divided into three subgroups according to CSF cell count: 1st group had a pleocytosis of 6-50 cells/µL, 2nd group-51-100 cells/µL, and 3rd group->100 cells/µL. A reference group involved 32 children (17 girls and 15 boys) aged from 2 to 18 years with a normal range of 0-5 cells/µL. Examination of CSF was performed in parallel by two different method, manual and automated.

Results: The analysis of pleocytosis revealed that the values obtained by the manual method were statistically significantly lower in relation to the values obtained by automated technique in subgroups I and II. The number of mononuclear and polymorphonuclear cells in subgroups I, II, and III determined by both manual and automated methods was comparable.

Conclusion: We conclude that automated method cannot fully replace the previously used manual method and some of the dubious cases, such as samples with low pleocytosis rates or abnormal cells indicated by the analyzer, will still require microscopic examination.

Keywords: automated method; cerebrospinal fluid; manual method; mononuclear cells; pleocytosis; polymorphonuclear cells.

Figure 1

Linearity of XT‐4000i counts in cerebrospinal fluid for pleocytosis, mononuclear cells, and polymorphonuclear cells counts. The identity line is drawn

Figure 2

Passing‐Bablok regression analysis showing the comparison of pleocytosis, mononuclear cells, and polymorphonuclear cells cells obtained with manual and automated methods in the study whole group and subgroups. The regression equation is given in bottom right corner. The solid line represents the fitted regression line. The dotted line represents the line of identity. The dashed lines represent the regression line confidence interval (95% CI for the regression line)

Figure 3

Bland‐Altman difference plots for pleocytosis, mononuclear cells, and polymorphonuclear cells cells obtained with manual and automated methods in the study whole group and subgroups. The solid line shows average of the differences obtained and corresponds to the bias between cells results obtained with two methods. The dashed lines correspond to the lower and upper limits of the confidence interval at 95% (mean ± 1.96 SD) of the difference between results obtained with two methods