ESTABLISHING ALBUMIN LEVELS IN SHEEP SERUM BY A SPECIFIC FLUOROIMMUNOASSAY

A rapid and sensitive fluoroimmunoassay (FIA) was developed to measure albumin levels in sheep serum. The assay employed ovine albumin label led with fluorescein as the tracer and a rabbit antiserum raised again st sheep albumin. Separation of antibody-bound from free albumin was a chieved using a second antiserum directed against the Fc component of rabbit IgG. Assay procedures were simplified by mixing the two antiser a prior to use. Satisfactory assay validation parameters were demonstr ated and the reagents were stable for at least 1 year at 4 degrees C. In contrast to the bromocresol green dye binding method, the accuracy of the FIA was unaffected by contaminating immunoglobulins. The FIA wa s used to establish reference ranges for serum albumin levels in lambs , in normal ewes and in ewes undergoing a prolonged course of immunisa tion. Mean serum albumin levels for these three groups were 38.8, 51.3 and 37.8 g L-1 respectively. The sensitivity of the assay makes it su itable to monitor albumin levels in therapeutic products derived from sheep blood or serum.