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The analysis of cells in the cerebrospinal fluid (CSF) is a routine procedure that is usually performed manually using the Fuchs-Rosenthal chamber and cell microscopy for cell counting and differentiation. In order to reduce the requirement for manual assessment, automated analyses by devices mainly used for blood cell analysis have been also used for CSF samples. Here, we summarize the current state of investigations using these automated devices and critically review their limitations. Despite technical improvements, the lower limit for reliable leukocyte counts in the CSF is still at approximately 20 cells/µL, to be validated depending on the device. Since the critical range for clinical decisions is in the range of 5-30 cells/µL this implies that cell numbers < 30/µL require a manual confirmation. Moreover, the lower limit of reliable erythrocyte detection by automated devices is at approximately 1000/µL. However, even low erythrocyte numbers may be of clinical importance. In contrast, heavily hemorrhagic samples from neurosurgery may be counted automatically at an acceptable precision more quickly. Finally, cell differentiation by automated devices provides only a rough orientation for lymphocytes, granulocytes and monocytes. Other diagnostically important cell types such as tumor cells, siderophages, blasts and others are not reliably detected. Thus, although the automation may give a gross estimate sufficient for the emergency room situation, each CSF requires a manual microscopy for cytological evaluation for the final report. In conclusion, although automated analysis of CSF cells may provide a first orientation of the cell profile in an individual sample, an additional manual cell count and a microscopic cytology are still required and represent the gold standard.

Competing Interests: Interessenkonflikt: Die Autoren geben an, dass kein Interessenkonflikt besteht.

Abstract Background Testing for cerebrospinal fluid (CSF)-restricted oligoclonal bands (OCB) by isoelectric focusing is used to detect intrathecally produced total IgG. By contrast, antibody indices (AI) are assessed to test for intrathecally produced antigen-specific IgG. A number of previous cases reports have suggested that AI testing might be more sensitive than OCB testing in detecting intrathecal IgG synthesis. Findings Here we report on 21 patients with positive AI for either herpes simplex virus, varicella zoster virus, cytomegalovirus, measles virus, rubella virus, or Borrelia burgdorferi in the absence of total-IgG OCB and, accordingly, in the presence of a normal total-IgG CSF/serum ratio. Conclusion Our findings indicate that AI testing should not generally be omitted in OCB-negative patients and provide a rationale for systematic and prospective studies on the comparative sensitivity and specificity of AI and total-IgG OCB testing in infectious and other diseases of the CNS.

Subarachnoid haemorrhage (SAH) has a high mortality and morbidity rate. Early SAH diagnosis allows the early treatment of a ruptured cerebral aneurysm, which improves the prognosis. Diagnostic cerebrospinal fluid (CSF) analyses may be performed after a negative computed tomography scan, but the precise analytical methods to be used have been debated. Here, we summarize the scientific evidence for different CSF methods for SAH diagnosis and describe their implementation in different countries. The principle literature search was conducted using PubMed and Scopus with the search items 'cerebrospinal fluid', 'subarachnoid haemorrhage', and 'diagnosis'. CSF analyses for SAH include visual examination, red blood cell counts, spectrophotometry for oxyhaemoglobin or bilirubin determination, CSF cytology, and ferritin measurement. The methods vary in availability and performance. There is a consensus that spectrophotometry has the highest diagnostic performance, but both oxyhaemoglobin and bilirubin determinations are susceptible to important confounding factors. Visual inspection of CSF for xanthochromia is still frequently used for diagnosis of SAH, but it is advised against because spectrophotometry has a superior diagnostic accuracy. A positive finding of CSF bilirubin is a strong indicator of an intracranial bleeding, whereas a positive finding of CSF oxyhaemoglobin may indicate an intracranial bleeding or a traumatic tap. Where spectrophotometry is not available, the combination of CSF cytology for erythrophages or siderophages and ferritin is a promising alternative. [ABSTRACT FROM AUTHOR]

Abstract: Background: 80–100% of patients with multiple sclerosis (MS) display a polyspecific, intrathecal humoral immune response against a broad panel of viral agents including antibodies to measles, rubella and varicella zoster virus as its three most abundant components (called MRZ reaction [MRZR]). However, a positive MRZR reaction can also be found in some patients with CNS vasculitis, another rare autoimmune condition, raising the question whether this marker is really of high specificity for MS as previously claimed or whether it just represents a non-specific marker of CNS autoimmunity. Besides MS and CNS vasculitis, paraneoplastic neurological disorders (PND) represent the best recognized models of CNS autoimmunity. Objective: To investigate MRZR for the first time in patients with PND. Patients and methods: Forty-two patients with MS and 34 with PND were compared in this study. The intrathecal synthesis of antibodies against measles, rubella, and varicella zoster virus was detected by calculation of the respective antibody indices (AI). Results: A positive MRZ reaction as defined by a combination of at least two positive AIs was present in 37/42 patients with MS, but in none of the patients with PND (p < 0.0001). Median AI values differed significantly between groups (p < 0.0005). Conclusions: Our results confirm that MRZR is not a general marker of CNS autoimmunity. Taking into account the very rarity of CNS vasculitis as well the lack of MRZR positivity in infectious inflammatory CNS conditions as previously demonstrated, MRZR might indeed be a promising marker of MS. Further investigations on MRZR in more rare autoimmune conditions, which were not available for analysis in this study, are now warranted to refine further the specificity of this parameter. [Copyright &y& Elsevier]