Total cell quantification in Cerebrospinal Fluid: Can Alinity hq be an effective alternative?

Abstract

Introduction: Cell quantification in the cerebrospinal fluid (CSF) is a critical method for the diagnosis of subarachnoid bleeding, neuro-inflammatory and neoplastic pathologies. Despite the numerous technological advances in automatic hematology analyzers, CSF cell count is still a manual microscopy procedure in several clinical pathology laboratories and therefore a technique not only time-consuming but also labour-intensive, requiring experienced laboratory staff and with a high intra- and inter-operator variability. Methods: To assess the possibility of automating the CSF cell count, a comparative-descriptive study was conducted to validate and implement the method. A comparison between the manual CSF cell counts method (reference method) and the Alinity hq automatic analyzer was performed on 222 samples from the Instituto Português de Oncologia de Lisboa Francisco Gentil. Data was analyzed statistically by Bland-Altman to determine the limits of agreement between both methods and the ability of Alinity hq (Abbott Laboratories, Diagnostics Division, Hematology, Santa Clara, CA, USA) to discriminate pathological samples (≥ 5 leucocytes/μL) from normal samples (< 5 leucocytes/μL).  Results: Leucocytes demonstrated a mean difference between manual count and automatic count of – 2,0 leucocytes/μL and an agreement of [-30,18 to 26,18 leucocytes/μL]. For erythrocyte counts, we obtained a mean difference of -106,36 erythrocytes/μL and an agreement of [-934,64 to 721,96 erythrocytes/μL]. Conclusion: The CSF's low cellular content and the clinically accepted reference values imposed for the method are a hindrance to implementing automation in clinical practice.