Secretin stimulation test used for -

Ans. is 'a' i.e., Gastrinoma Gastrin Provoking tests* Gastrin provocative tests have been developed in an effort to differentiate between the causes of hypergastrinemia.* The tests are the secretin stimulation test and the calcium infusion study.* The most sensitive and specific gastrin provocative test for the diagnosis of gastrinoma is the secretin study. An increase in gastrin of >120 pg within 15 minutes of secretin injection has a sensitivity and specificity of >90% for ZES. PPI induced hypochlorhydria or achlorhydria may lead to a false-positive secretin test, thus this agent must be stopped for 1 week before testing.* The calcium infusion study is less sensitive and specific than the secretin test, which coupled with it being a more cumbersome study with greater potential for adverse effects, relegates it to rare utilization in the cases where the patient's clinical characteristics are highly suggestive of ZES, but the secretin stimulation is inconclusive.