In the current study, the quantification of C-reactive protein (CRP) in cerebrospinal fluid (CSF) of dogs using an adapted time-resolved immunofluorimetric assay (TR-IFMA) was investigated, as well as whether the assay could be used to detect the range of CRP concentrations found in different clinical situations. Intra- and interassay coefficients of variation were below 15% in all cases. The TR-IFMA measured the CRP values in a proportional and linear manner (r = 0.99); also CRP concentrations measured in CSF and in serum were significantly correlated (r = 0.80, P = 0.003). The limit of detection of the method was 7.1 × 10(-6) mg/l. The assay was able to detect differences in CRP concentrations in CSF of dogs with inflammatory disorders compared with dogs with spinal cord compression or idiopathic epilepsy. In conclusion, TR-IFMA constitutes a very sensitive, precise, and accurate method for the measurement of CRP concentrations in CSF.