The nonselective, passive process performed by the glomerulus that forms blood plasma without blood proteins is called filtration.
Glomerular filtration is the first step in making urine which includes the separation of the liquid part of the blood (plasma) from the blood cells. Glomerulus of the kidneys (a tuft of blood capillaries) filters excess fluid and waste products out of the blood into the urine collecting tubules of the kidney and thus eliminates it out of the body.