A Cross-sectional Study on the Positive Rate of M Protein Based on a Highly Sensitive Serum M Protein Detection Method.

This study uses a highly sensitive blood test to measure how common abnormal proteins called "M proteins" are in the general hospital population. M proteins in the blood can be an early sign of certain blood disorders. Researchers want to understand how often these are found using a newer, more sensitive testing method. **You may be eligible if...** - You are 18 years or older - You are being seen at Zhujiang Hospital (in China) as an outpatient, emergency, or inpatient - There is leftover blood (serum) from your routine tests available and you have given general consent for research use **You may NOT be eligible if...** - You have already been diagnosed with a blood cancer involving plasma cells or B lymphocytes (such as myeloma or lymphoma) - Your blood sample was stored improperly or has been repeatedly frozen and thawed Talk to your doctor to see if this trial is right for you.