Advantages of serum pepsinogen A combined with gastrin or pepsinogen C as first-line analytes in the evaluation of suspected cobalamin deficiency: a study in patients previously not subjected to gastrointestinal surgery.

Abstract

OBJECTIVES: Since there is a significant overlap in serum cobalamin concentrations between healthy and cobalamin-deficient individuals, we wanted to compare two different principles for use as supplementary tests to serum cobalamin concentration in patients with suspected cobalamin malabsorption and deficiency. DESIGN: Clinical study of consecutive patients. SETTING: The catchment area of Sahlgrenska University Hospital, Göteborg. SUBJECTS: A total of 112 patients with suspected cobalamin deficiency who had not previously undergone gastrointestinal surgery. INTERVENTIONS: Gastroduodenoscopy with biopsies taken from the gastric body and the duodenum, Schilling test, and measurement of serum methylmalonic acid (MMA), total homocysteine (Hcy), pepsinogens A and C, and gastrin. MAIN OUTCOME MEASURES: Number of patients with gastric body atrophy identified with the combination of MMA and Hcy, and pepsinogen A combined with pepsinogen C or gastrin. RESULTS: About 95% of the patients with severe gastric body atrophy had abnormal concentrations of serum pepsinogen A and/or gastrin or pepsinogen A/C ratio, whereas 65% had abnormal metabolite concentrations. Serum pepsinogen A combined with pepsinogen C identified 100%, and combined with gastrin 88%, of the patients with gastric body atrophy and elevated metabolite tests, and 67 and 75%, respectively, of those who had not yet developed elevated metabolite tests. CONCLUSIONS: Pepsinogen A, combined with pepsinogen C or gastrin, should be the first option in evaluating patients with suspected cobalamin deficiency who have not previously undergone gastrointestinal surgery.