Storage artefacts in peripheral blood smears

Introduction: Microscopic evaluation of peripheral blood smear is a very important investigation. Blood for various laboratory analyses are commonly kept in ethylene diamine tetra acetic acid (EDTA). EDTA can however cause morphological and fragility changes in blood cells. However, morphological analyses can be greatly hampered due to occurrence of artefacts. Aims and Objectives: To identify the storage artefacts and thus avoid misinterpretation of peripheral blood smears. Materials and Methods: 50 blood samples were obtained using EDTA and 3.5% sodium citrate as anticoagulants. Smears were made immediately as well as after 2, 4 and 6hrs of storage at room temperature. Smears obtained from same patients by finger prick method served as controls. Conclusion: EDTA has been recommended as the anticoagulant of choice for peripheral smear but should be examined within 1hr of collection to avoid misinterpretation as pathological findings leading to wrong diagnosis.