In three control groups of lumbar (L), cisternal (C), and ventricular (V) cerebrospinal fluid (CSF) with prealbumin contents of ventricular origin (CSF-V-prealbumin) within the reference range, indications for an increased transport of V-CSF into spinal space are presented in the elderly as well as an elevated production of V-CSF. Indications for a diminished V-CSF production, respectively, an increased transport of CSF-V-prealbumin into the spinal space were found in elderly patients suffering from diverse CNS diseases. As these alterations proved to be not disease-specific, the age-related increase of CSF transport was discussed with respect to brain atrophy and enlarged CSF spaces in the elderly central nervous system (CNS). CSF serum prealbumin content, an indicator of blood-brain-barrier function, increased with age similarly to albumin in the "normal" elderly, respectively with diverse CNS diseases. Age- and disease-related decreases of albumin and prealbumin contents in blood serum may lead to wrong interpretations.