Megaloblasts in the Peripheral Blood

THE finding of megaloblasts in the peripheral blood is often regarded as an uncommon event, confined to patients with severe anaemia. Methods of concenitrating the megaloblasts by making preparations from the "buffy coat'i of the haematocrit have been described (Goodall, 1957, Whitby and Britton, 1957). This paper records our experience of examining the peripheral blood for megaloblasts. METHOD. It has been our custom for a number of years to examine carefully the routine blood film from patients with anaemia where there is macrocytosis or a dimorphic picture, or if the neutrophils show a shift to the right. In many of these, megaloblasts were found in the tail or along the edges of the film. If no megaloblasts are found, "buffy coat" preparations are made as described by Goodall (1957) and if these are negative the bone marrow is examined. The routine blood film is made either from an ear prick, or from venous blood within two hours of collection, using Sequestrene (EDTA) as anticoagulant. Red cell counts and absolute values are not done routinely. REsULTS. During the calendar years 1957, 1958, and 1959 there were 247 cases of niegaloblastic anxemia diagnosed in this laboratory. Method of Diagnosis. Routine blood film-104 (42 per cent.) "Buffy coat" preparation-35 (14 per cent.) Bone marrow examination-108 (44 per cent.) Discus S ION. The table shows that over half of the cases were diagnosed by examination of the peripheral blood alone and in the majority of these megaloblasts were found in the routine blood film. The response to specific treatment and subsequent course of these patients indicated that the diagnosis was correct. The degree of anaemia was not always severe; many patients had ha!moglobin levels over 7g. at the time of diagnosis. We feel that the procedures described reduce the amount of technical work by eliminating red cell counts and absolute values, and spare the patient the discomfort of marrow examination. SUMMARY. Megaloblasts were present in the peripheral blood in 139 out of 247 cases of megaloblastic anxmia. In 104 of these, megaloblasts were seen in the routine blood film. They were present in "buffy coat" preparations from the other 35 cases. REFERENCES.