Zollinger-Ellison syndrome: Likelihood Ratios

Introduction: Zollinger-Ellison syndrome is the entity of a gastrin-secreting tumor causing peptic ulcers (and often diarrhea). It occurs in patients with MEN1.

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The likelihood ratios of findings for Zollinger-Ellison syndrome are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Poorly Diagnostic Findings
Finding	Result	+LR	-LR
[ + ] Elevated Fasting Serum Gastrin		Sensitivity = 97%
above upper limit of normal. No specificity mentioned but 2/3 of patients have elevated fasting gastrin < 10x upper limit, which overlaps with H pylori or G cell hyperplasia. Also must ensure that gastric pH is normal for this test to be valid. Study: Medicine (Baltimore). 2006 Nov;85(6):295-330. PMID 17108778

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] Secretin Stimulation Test	+ 0 -	inf	0.1
gastrin rise > 120 pg/ml (in normal patients, secretin should inhibit gastrin production) Sensitivity is only 83% if cutoff is >200pg/ml rise. Study: Medicine (Baltimore). 2006 Nov;85(6):331-64. PMID 17108779
[ + ] Secretin Stimulation Test	+ 0 -	12.3	0.2
gastrin rise > 50% over baseline Study: Medicine (Baltimore). 2006 Nov;85(6):331-64. PMID 17108779
[ + ] Calcium Infusion Study	+ 0 -	4.6	0.3
gastrin rise >= 50% above baseline Study: Medicine (Baltimore). 2006 Nov;85(6):331-64. PMID 17108779
[ + ] Calcium Infusion Study	+ 0 -	inf	0.4
rise in gastrin >= 395 pg/ml The test is performed by infusing calcium gluconate (5 mg/kg body weight per hour for three hours) and determining serum gastrin levels every 30 minutes. Study: Medicine (Baltimore). 2006 Nov;85(6):331-64. PMID 17108779