Multiple myeloma is mostly seen in middle-aged and elderly patients over 40 years old, mostly between 50 and 60 years old, with complex and variable manifestations and lack of specificity, especially in the early stage when it often shows only one symptom, which is very easy to cause leakage and misdiagnosis, and some domestic reports show that the misdiagnosis rate of multiple myeloma can be as high as 70%. Patients with atypical clinical symptoms such as lung infection, low back pain and anemia should pay high attention to the following conditions. 1. Infection: The main manifestations are recurrent infections of respiratory and urinary tracts, and the appearance of these symptoms is actually due to the malignant proliferation of myeloma cells, which secrete a large amount of monoclonal immunoglobulins, while the secretion of normal immunoglobulins decreases and myeloma infiltration leads to a decrease in leukocyte production and suppression of both humoral and cellular immunity, resulting in a decrease in the immunity of the body. In this case, if only a systemic infection is diagnosed and anti-infective treatment is given without looking for the cause of the infection, the diagnosis is easily missed. Therefore, patients with recurrent bleeding respiratory and urinary tract infections, especially the elderly, should visit the hematology department promptly; 2. Inhibition of osteoblasts. The intensity of bone pain is often related to the degree of disease progression. A sudden increase in bone pain is often indicative of a pathological fracture. Patients often present to orthopedics with bone pain and are misdiagnosed with osteoporosis, osteomalacia, muscle strain, lumbar disc herniation, fracture, rheumatoid arthritis, or bone metastases based solely on impactology. Therefore, for patients with skeletal pain without history of trauma and also suffering from anemia, they should go to hematology department as soon as possible; 3. Nephropathy: renal damage caused by multiple myeloma is mainly related to the nephrotoxic effect of free immunoglobulin light chains in plasma via glomerular filtration on renal tubules, multiple myeloma combined with renal function damage has the following characteristics: generally blood pressure is not high, anemia is not proportional to the degree of renal damage, both kidneys are not If not taken seriously, it is easy to be misdiagnosed as chronic nephritis; 4. Anemia: Anemia is mainly due to the suppression of the bone marrow hematopoietic system, which reduces blood cells. Clinically, it is often manifested as dizziness, weakness, panic, nose bleeding, gum bleeding and skin purpura, etc. It is easily misdiagnosed as leukemia, myelodysplastic syndrome, aplastic anemia and hemolytic anemia, etc. A few patients are easily misdiagnosed as renal anemia. If there is renal impairment and anemia, blood sedimentation should be checked early. If the blood sedimentation is particularly fast (80-100mm/h), the possibility of multiple myeloma should be highly suspected. 5. Others: Due to hyperviscosity, malignant plasma cell infiltration of the myocardium and myocardial amyloidosis, cardiac insufficiency can be induced and easily misdiagnosed as coronary heart disease and cardiomyopathy, and a few cases are misdiagnosed as liver cirrhosis because of low serum protein and high globulin. (1) persistent unexplained back pain with weight loss or osteoporosis; (2) recurrent or persistent bacterial infections, typical anemia and/or leukocytopenia; (3) persistent blood sedimentation or increased blood viscosity; (4) hypercalcemia; (5) renal impairment, etc.