The polychromatism of postmortem cerebrospinal fluid

Based on the assumption that postmortem cerebrospinal fluid (CSF) is contaminated depending on the chosen sampling technique in the forensic setting resulting in bloody or at least hemolytic CSF samples, we systematically documented a total of 183 postmortem CSF samples. These samples were all assessed for their quality and color, regardless of the cause of death or the postmortem interval. The investigations were carried out through subjective assessment of color and turbidity, as well as objective measurements of the optical density (OD) of the CSF supernatants after centrifugation of each sample, with standardized photographic documentation. The observations revealed that in 28 cases the CSF was absolutely (crystal-) clear and transparent. Most of our samples showed color changes ranging from xanthrochromic to rose. Intensive staining of the supernatants was only found in a small proportion of the examined collective. We found that postmortem CSF has no uniform appearance but rather a diverse range of color spectra, and the color, as well as the OD of the CSF, correlates significantly with the postmortem interval (p < 0.001) when sampled using the proposed standard procedure.