AUTHOR=Schwenkenbecher Philipp , Janssen Theda , Wurster Ulrich , Konen Felix Franz , Neyazi Alexandra , Ahlbrecht Jonas , Puppe Wolfram , Bönig Lena , Sühs Kurt-Wolfram , Stangel Martin , Ganzenmueller Tina , Skripuletz Thomas 

TITLE=The Influence of Blood Contamination on Cerebrospinal Fluid Diagnostics

JOURNAL=Frontiers in Neurology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2019.00584

DOI=10.3389/fneur.2019.00584

ISSN=1664-2295

ABSTRACT=<p><bold>Background:</bold> Blood contamination due to traumatic lumbar puncture presents a diagnostic pitfall in cerebrospinal fluid (CSF) analysis. It is controversially discussed if phagocytosis of erythrocytes which can be found in the CSF after subarachnoid hemorrhage can also develop <italic>in vitro</italic> in the presence of artificial blood contamination. Furthermore, there is no consensus about the acceptable amount of artificial blood contamination on CSF protein results.</p><p><bold>Methods:</bold> Two measurement series were performed in order to investigate the role of artificial blood contamination on the possible development of erythrophages and siderophages in the CSF: (1) blood contamination was simulated <italic>in vitro</italic> by adding blood into the CSF. (2) CSF was investigated when blood contamination occurred during a traumatic lumbar puncture. In both types of experiments, CSF including blood was incubated for 24 h and for 72 h at room temperature or at 4°C. In the third measurement series, the effects of artificial blood contamination on CSF protein results were investigated. Blood contamination was simulated <italic>in vitro</italic> by adding different amounts of blood ending up with five different samples containing erythrocyte counts of 2,500, 5,000, 7,500, 10,000, and 20,000 per μl CSF.</p><p><bold>Results:</bold> Cytological examination revealed no evidence of erythrophages or siderophages <italic>in vitro</italic>. In contrast, already a low blood contamination (2,500 erythrocytes/μl CSF) led to false pathological results of total protein and albumin. Along with increasing amounts of blood, the frequency of false pathological protein results increased. A blood contamination of 5,000 erythrocytes/μl CSF resulted in a false positive intrathecal IgM production in nearly every fifth patient. In contrast, blood contamination with 5,000 erythrocytes/μl CSF was the acceptable amount of blood which did not lead to a false positive intrathecal synthesis of IgG and IgA.</p><p><bold>Conclusion:</bold> Erythrophages and siderophages do not develop <italic>in vitro</italic>. An extensive diagnostic work up for the source of blood in the CSF should be performed when erythrophages or siderophages are found in the CSF. The contamination of CSF with increasing volume of blood resulted in falsely elevated CSF protein concentrations. Hence, the amount of blood contamination has to be taken into consideration when interpreting CSF protein measurement results.</p>