American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What serum gastrin level is indicative of Zollinger-Ellison syndrome?

1. Above 500 pg/mL

2. Above 1000 pg/mL

3. Above 1500 pg/mL

4. Above 2000 pg/mL

The correct answer is: Above 1000 pg/mL

In Zollinger-Ellison syndrome, which is characterized by gastrin-secreting tumors (gastrinomas), elevated levels of serum gastrin are a key indicator of the condition. A gastrin level greater than 1000 pg/mL is typically used as a diagnostic threshold for Zollinger-Ellison syndrome. This level signifies excessive gastrin production that leads to gastric acid hypersecretion, resulting in recurrent peptic ulcers and other gastrointestinal symptoms. While levels above 500 pg/mL can be seen in other conditions such as atrophic gastritis, the definitive threshold that strongly suggests the presence of gastrinomas is set at greater than 1000 pg/mL. This value provides a clear demarcation in the clinical evaluation, allowing healthcare providers to differentiate between Zollinger-Ellison syndrome and other causes of hypergastrinemia. Levels higher than 1000 pg/mL lend further support to a diagnosis of gastrinoma, particularly when considered alongside clinical findings and imaging studies.