The deoxyuridine suppression test in peripheral lymphocytes.

The effects of different deoxyuridine (dU) concentrations on lymphocytes stimulated with phytohemagglutinin (PHA) were studied for use in a lymphocyte dU suppression test (L-dUST). High concentrations of dU were necessary to overcome the unspecific spontaneous pattern of folate deficiency, dU suppression tests with cells of bone marrow (BM-dUST) and with lymphocytes were carried out in 15 patients with vitamin B-12 deficiency, in 12 with folate deficiency, and in 10 with other pathological conditions. L-dUST was also carried out in 15 healthy reference controls. The BM-dUST was able to distinguish patients with vitamin B-12 or folate acid deficiencies from those without, while the L-dUST was unable to do so in most cases. L-dUST does not, therefore, appear to be a reliable method for the diagnosis of megaloblastic changes.