Isotachophoresis in polyacrylamide gel tubes (PAG-ITP) and in capillary tubes (Tachophor, LKB) have previously been found by the authors, to be very promising high-separation methods for CSF and serum proteins, especially regarding the diagnosis of MS. PAG-ITP methods for analytical and preparative use have been described by the authors elsewhere, while in this paper proper cationic systems for ITP in capillary tubes for studying gammaglobulins in microliter amounts of CSF and serum are described, i.e. the albumin injection-clog problem is avoided and the preparation time can be forced. By using microdialysis of the CSF samples for desalting, with a technique easy to perform and with high reproducibility, microliter amounts of native CSF can be performed in less than half an hour. The method seems to be even more applicable for clinical and scientific use if the capillary isotachophoretic apparatus is connected to a synchronized equipment (LKB Tachophrac) with a cellulosa acetate strip onto which the separated fractions are ejected for further analysis by immunological tests. The analytical systems used have been especially directed to gammaglobulins in CSF and serum regarding further studies on demyelinating and infectious disorders of the nervous system.