Basic ferritin content of red cells of patients with anemia and polycythemia vera.

Basic ferritin content of red cells has been evaluated with a simplified assay in subjects with various erythroid disorders. In 39 patients with iron deficiency anemia, red cell ferritin was significantly reduced compared with that of normal individuals. Thirty percent of these patients had low normal red cell ferritin content and the MCV for this group was significantly higher than that of patients with reduced red cell ferritin. The mean red cell ferritin of 30 subjects with the anemia of chronic disease was significantly reduced and patients in this group with normal red cell ferritin had higher plasma ferritin levels. In 14 patients with polycythemia vera, the mean red cell ferritin was significantly reduced and showed a positive correlation with the hemoglobin level and percent transferrin saturation. The red cell ferritin content of 9 individuals with acquired immune hemolytic anemia and 10 with acquired sideroblastic anemia was significantly elevated and, in subjects with immune hemolysis, showed a positive correlation with the reticulocyte count. These findings suggest a lack of discriminatory function for red cell ferritin in iron deficiency anemia and anemia of chronic disease. Evaluation of this parameter in the individual patient should take into account the presence of reticulocytosis.

Red cell ferritin content: a re-evaluation of indices for iron deficiency in the anaemia of rheumatoid arthritis.

In iron deficiency anaemia basic red cell content of ferritin is appreciably reduced. This variable was determined in 62 patients with rheumatoid arthritis to evaluate conventional laboratory indices for iron deficiency in the anaemia of rheumatoid arthritis. For 23 patients with rheumatoid arthritis and normocytic anaemia irrespective of plasma ferritin concentration, red cell ferritin content did not differ significantly from that for non-anaemic patients with rheumatoid arthritis. For 27 patients with rheumatoid arthritis and microcytic anaemia, the mean red cell ferritin content for patients with a plasma ferritin concentration in the 13-110 micrograms/l range was appreciably reduced. It was indistinguishable from that for patients with rheumatoid arthritis and classical iron deficiency anaemia, indicated by plasma ferritin concentrations of less than 12 micrograms/l. In contrast, the mean red cell ferritin content for patients with rheumatoid arthritis, microcytic anaemia, and plasma ferritin concentrations above 110 micrograms/l did not differ from that for patients with rheumatoid arthritis and normocytic anaemia. Oral treatment with iron in patients with rheumatoid arthritis, microcytic anaemia, and appreciably reduced red cell ferritin concentrations was accompanied by significant increases in haemoglobin concentration (p less than 0.01), mean corpuscular volume (p less than 0.01), and red cell ferritin contents (p less than 0.05). This treatment, however, did not produce any appreciable change in haemoglobin concentration in patients with rheumatoid arthritis, normocytic anaemia, and normal red cell ferritin contents. These findings suggest that the indices for iron deficiency in patients with rheumatoid arthritis and anaemia should include peripheral blood microcytosis together with a plasma ferritin concentration of less than 110 micrograms/l.

Influence of urinary sodium on calcium excretion in normal individuals. A redefinition of hypercalciuria.

The twenty-four hour urinary excretion of calcium and sodium was measured in 38 normal volunteers after a week on a diet containing 400 mg of calcium per day. There was a significant correlation (P less than 0.001) between calcium and sodium excretion. The normal range of calcium excretion as a function of sodium excretion has been determined. This approach sharpens the definition of hypercalciuria by taking into account the influence of dietary sodium intake. It also removes the necessity of regulating dietary sodium as well as calcium intake before measuring calcium excretion in patients who form recurrent renal stones.

Problems encountered in the immunoassay of alpha-foetoprotein in patients with hepatoma.

Immunoradiometric assays suffer from the phenomenon of paradoxical increase in count rate with increasing dilution of highly concentrated samples--the "hook-effect". This is particularly important for alpha-foetoprotein where in hepatoma may be thousands of times the upper limit of the range of immunoradiometric assays. Using a commercial kit method we have encountered some degree of hook effect in many patients with hepatoma. Significant hooking occurred after 1,000 to 2,000 micrograms/1 but the extent of the effect was sample dependent. Of the samples tested so far, only one patient produced a hook which extended into the standard curve counts range. This resulted in a measured values of 20 micrograms/1 (value on dilution: 100,000 micrograms/1). We recommend that this method should be used routinely in conjunction with a screening method e.g., counterimmunoelectrophoresis and that quantitation of very high values should be by radial immunodiffusion or a method with similar sensitivity.