Comparison of the measurement of serum cotinine levels by gas chromatography and radioimmunoassay.

Standard cotinine solutions, controls and human serum samples containing cotinine have been measured by both radioimmunoassay (RIA) and gas chromatographic (GC) techniques. Cross-checks on standards and controls showed good agreement. However, for samples containing greater than 50 ng ml-1 of cotinine, RIA gave results on average 60% higher than GC.

Evaluation of pituitary-adrenal function after pituitary surgery.

A short overnight metyrapone test and a 30-min ACTH test were performed in ten patients after pituitary surgery. At the initial testing 2 weeks after surgery the 30-min ACTH test was abnormal in two patients while normal increases in s-cortisol were observed in eight patients. These eight patients also had normal responses to ACTH when re-tested after 6-19 months.