A sensitive assay of transthyretin (prealbumin) in human cerebrospinal fluid in nanogram amounts by ELISA

A sensitive ELISA method for determining transthyretin (prealbumin) in human cerebrospinal fluid (CSF) is described. The method utilizes goat antihuman transthyretin antibody (IgG fraction) for capture and peroxidase conjugated antibody for color development. The assay has a linear range of 1-4 ng transthyretin added per well. The within-day and between-day coefficients of variation are 5.1 and 6.1%, respectively. The concentration of transthyretin in CSF (ranging from 5 to 20 mg per L) correlated significantly with the corresponding serum concentrations (range 170-420 mg/l). This suggests that synthesis of transthyretin in the brain and peripheral tissues is under similar biological control in normal subjects. The transthyretin concentrations in CSF did not correlate with total CSF protein concentration or age of the subject.