The value of 5-hydroxyindolacetic acid analysis in urine. A clinical and cost-benefit study.

The clinical value and the cost-benefit of 5-hydroxyindolacetic acid in urine (5-HIAA/u) measurements in diagnosing carcinoid tumours were analysed. During a 5-month period a total of 1397 analyses yielded 62 patients with elevated 5-HIAA/u levels, of which 28 patients had previously been operated on for a carcinoid tumour. Only one carcinoid tumour was found to have been diagnosed on the evidence of elevated 5-HIAA/u levels. In patients previously operated on for carcinoid tumour, elevated leves of 5-HIAA/u did not influence their treatment. Several border-line values were probably due to a temporary decline in hepatic function or to substances interfering with the analytical methods used. It is concluded that 5-HIAA/u measurements are of limited clinical value.