Low serum B12 level and normal Schilling's test.

Abstract

To the Editor:—I read with interest the article by Marcus et al titled “Low Serum B12 in Hematologically Normal Elderly Subpopulation.”1A retrospective review of patient charts at our hospital indicates a high frequency of low serum B12 and a normal Schilling's test in our patient population. From January 1982 to April 1987 there were 41 patients who had Schilling's test and low serum B12. Eighteen of the 45 patients with low serum B12 level (the largest subgroup), had a normal Schilling's test. In the remaining patients the low serum B12 was due to pernicious anemia (in 12), malabsorption (in four), gastrectomy (in two), and dietary B12 deficiency (in one). In four patients the urine collection was incomplete. Of the 18 patients with low B12 value and normal Schilling's test, charts were available on 17 for review. Four of the 17 had anemia (Hb of less than 13 g/dL). One of the four had macrocytic index. All were males, with mean age of 73 years (range 59 to 91 years). The majority of the patients were inpatients on an acute medical ward. None had discharge diagnosis of pernicious anemia. This patient group is probably similar to the elderly subpopulation group described in the article. At our institution, which consists of 443 beds acute medicine, surgery, psychiatry and some long-term care, a low B12 is more often seen in the “hemotologically normal elderly” and is generally not due to pernicious anemia. Only a long term follow up of these patients can clarify if the low B12 level produces any significant hematologic disorder.