When the concentration of macromolecular proteins in the plasma increases the negative charge on the surface of red blood cells decreases, the electrostatic repulsion between red blood cells decreases, thus resulting in increased aggregation of red blood cells, which tends to form strings or pile up into blocks. In patients with multiple myeloma nephropathy, blood smears may show strings of red blood cells, and later white blood cells and platelets are also reduced. Stringing of red blood cells can interfere with blood typing. Various sub-health symptoms, microscopic diagnosis may also show red blood cells lemonlike, red blood cells in the form of money strings or in piles. Specific examination methods are as follows: 1, erythrocyte volume index erythrocyte average index (value) is based on the red blood cell count, hemoglobin, Hct calculation of the average erythrocyte volume, average erythrocyte hemoglobin content, average erythrocyte hemoglobin concentration. 2, erythrocyte osmotic fragility test This test determines the resistance of erythrocytes to various concentrations of hypotonic solutions. In hypotonic saline, water passes through the cell membrane, causing the erythrocytes to gradually swell and destroy. The permeability of erythrocytes depends mainly on the ratio of surface area to volume of erythrocytes. Those with a large surface area and a small volume are more resistant to osmotic saline solutions and vice versa (increased fragility). Spherical erythrocytes with a reduced surface area/volume ratio are particularly sensitive to hypotonic solutions and have a significant increase in fragility. 3, Erythrocyte enolase Erythrocyte enolase (EC) is a cleaving enzyme in cellular lysosomes. Elevated total enolase (Enolase) activity often coincides with elevated neuron-specific enolase activity, and is most commonly seen in patients with small-cell lung cancer and neuroblastoma. After isolation of the serum, it is usually detected by chemiluminescence.