Why do urine contains protein?What does the term "Kidney-Level IV status" mean?Please explain kidney function

Answer to your first question is:- Healthy kidneys take wastes out of the blood but leave protein. Impaired kidneys may fail to separate a blood protein called albumin from the wastes. At first, only small amounts of albumin may leak into the urine, a condition known as microalbuminuria, a sign of deteriorating kidney function. As kidney function worsens, the amount of albumin and other proteins in the urine increases, and the condition is called proteinuria. Answer to 2nd question is:- Stage IV: There are several combinations of T, N, and M categories that included in this stage. This stage includes any cancers that have spread directly through the fatty tissue and the fascia ligament-like tissue that surrounds the kidney. Stage IV also includes any cancer that has spread to more than one lymph node near the kidney, to any lymph node not near the kidney, or to any other organs such as the lungs, bone, or brain. Detailed definitions of renal cell cancer T, N, M categories and stage groupings Answer to your 3rd question is :-- Most people have two functional kidneys. The kidneys produce urine that drains through narrow tubes (called ureters) into the bladder. The kidneys are usually located in each flank protected by muscles of the back and ribcage. The kidneys are contained within a fibrous sheath called the Gerota's fascia and surrounded by a layer of fat. The kidney capsule is a thin layer that covers the outer surface of the kidney (similar to the red peel of an apple). The primary vein that drains the kidney (renal vein) merges with the vein that takes blood to the heart (vena cava). An adrenal gland is located above each kidney within Gerota's fascia. The adrenal glands, which are not part of the kidney, are located near the top of each kidney. The adrenal glands regulate blood sugar, potassium, body fluids and sex hormones. They also control the body's response to stress by producing a hormone called adrenaline. The kidney performs many bodily functions, such as controlling fluid balance, regulating electrolytes (e.g., sodium, potassium, calcium, magnesium), preventing acid buildup, eliminating waste products, producing urine, and regulating blood pressure. The kidney also manufactures a hormone called erythropoietin that stimulates the production of red blood cells. When the kidneys are damaged or a significant portion of kidney tissue is removed, the normal processes listed above may be impaired. In most cases, mild to moderate impairment causes very minor problems. In cases when kidney function is severely impaired, dialysis may be required. More details at :--