The effect of preanalytical phase on the stability of the osmotic fragility and morphological changes in erythrocytes in cattle (Bos taurus)

Abstract

Hereditary spherocytosis in cattle is a disorder resulting from a nonsense mutation in the SLC4A1 gene, which encodes band 3 membrane protein. This membranopathy leads to the production of spherically-shaped RBCs with reduced deformability and a shorter lifespan in circulation. Laboratory diagnosis of hereditary spherocytosis commonly relies on the erythrocyte osmotic fragility test (OFT), which is time- and labour-consuming and can be influenced by preanalytical factors. The aim of the study was to determine the effect of the preanalytical phase on the stability of osmotic fragility and morphological changes in bovine erythrocytes. Blood was collected from the tail vein of Holstein-Friesian cows (n = 20) into tubes with EDTA or lithium heparin. Erythrocyte resistance to haemolysis was measured by the osmotic fragility test immediately after blood collection and 24, 48 and 72 hours after storage at 4C or at room temperature. Thin blood smears were also prepared, stained and examined for cell morphology. The results showed that bovine erythrocyte osmotic fragility remains stable during 24-hour storage at 4C irrespective of the anticoagulant used. This suggests that OFT can be performed the day after blood collection if blood is stored at 4C. Bovine erythrocytes stored at room temperature were also found to have reduced osmotic resistance. However, heparin better preserves the osmotic resistance of bovine erythrocytes at room temperature. Erythrocytes undergo changes during storage. The microscopic examination of cell morphology revealed rapid transformation of bovine discocytes into various stages of echinocytes during the first three days of storage.

Keywords

• bovine RBCs
• hemolysis
• osmotic resistance
• echinocytosis