A 45-year-old gentleman has undergone truncal vagotomy and pyloroplasty for bleeding duodenal ulcer seven years ago. Now he has intractable recurrent symptoms of peptic ulcer. All of the following suggest the diagnosis of Zollinger Ellison syndrome, except:
Diagnosis of ZES is made by secretin provocative test when serum gastrin value increases ≥ 200 pg/ml, within 15 minutes 
Zollinger Ellison syndrome

ZES is caused by gastrin secreting gut neuroendocrine tumors (gastrinomas), which result in hypergastrinemia and acid hypersecretion.
Clinical situations that create suspicion for ZES are
ulcers in unusual locations, ulcers in second part of duodenum & beyond (includes the option c)
ulcers refractory to standard medical therapy
ulcer recurrance after acid reducing surgery.
ulcers presenting with frank complications (bleeding, perforation and obstruction) ulcers in the absence of H. pylori or NSAID ingestion.
giant ulcers (> 2 cm)
multiple duodenal ulcers
ulcers associated with diarrhoea
ulcer patient with hypercalcemia or family h/o ulcers.
ulcers with severe esophagitis.
ulcers associated with prominent gastric folds
ulcers with findings s/o MEN-1 (endocrinopathy, family h/o ulcers or endocrinopathy, nephrolithiasis)

Diagnosis of ZES (gastrinoma)

The first step in evaluation of a patient suspected of having ZES or gastrinoma is to obtain as fasting gastrin level.
All gastrinoma patients have a fasting gastrin level > 150 pg/mL.
The next step is to assess acid secretion by measuring basal acid output (BAD) which should be ≥15 meq/h (normal < 4 meq/h)

A gastric pH of ≥ 3.0 implies hypochlorhydria and excludes gastrinoma.
Gastrin Provocative tests

In a pt. with pH < 2.0 or BAO ≥ 15 meq/hr and fasting gastrin level > 1000 pg/mL, the diagnosis of LES is confirmed.
With pH < 2.0 or BAO ≥ 15 meq/L and lower gastrin levels (150-1000 pg/mL), a secretin stimulation test is perforfmed to distinguish LES from other causes of hypergastrinemia.
A rise of  ≥200 pg/mL of serum gastrin level within 15 min of secretin injection, confirms ZES.
Basal acid output of 15 meq/hour
Serum gastrin value of 500 pg/ml
Ulcers in proximal jejunum and lower end of esophagus
Serum gastrin value of 200 pg/ml with secretin stimulation