Plasma secretin determination as a test of gastric acid secretion: effect of a marker perfusion technique on validation.

OBJECTIVE

To examine whether plasma secretin levels can be used as a diagnostic measure of gastric acid output.

METHODS

A marker perfusion technique was used to quantify gastric acid output. Blood samples were drawn for secretin radioimmunoassay at specified intervals before and after pentagastrin stimulation in six healthy volunteers and six patients suspected of having abnormal gastric acid secretion.

RESULTS

Linear relationships were found between integrated secretin response and maximal acid output as well as between peak acid output and acid output at 2 h (P < 0.01). Similar correlations were also observed with secretin levels 52, 60 and 68 min after pentagastrin stimulation. Discrimination between low, average and high gastric acid secretors was possible at 52 and 60 min after stimulation. Plasma secretin did not increase after pentagastrin stimulation in the 12 subjects when acid was continually aspirated, nor did correction for gastric acid loss improve the correlation or discrimination.

CONCLUSION

One or two measurements of plasma secretin about 1 h after pentagastrin administration may provide a useful quantitative estimate of gastric secretory capacity for epidemiological or clinical purposes.