Oxalate-loading tests to screen for steatorrhoea: an appraisal.

We have evaluated two procedures as screening tests for steatorrhoea: firstly, a simplified, two-day, oxalate-loading test and secondly the rate of urinary oxalate excretion following a single oral dose of oxalate. Following two-day oxalate loading there was almost complete overlap of the values for 24-h urinary oxalate between 15 apparently healthy volunteers and 10 patients with steatorrhoea. The rate of oxalate excretion following a single dose of oxalate was increased in one patient with Crohn's disease and ileal resection who had normal faecal fat excretion, but three patients with steatorrhoea due to other causes had normal rates of excretion. We conclude that these oxalate-loading tests are not a useful alternative to faecal fat estimation in patients with suspected malabsorption.