Albuminuria (proteinuria) is caused by kidney damage, specifically when the damage occurs in the glomerulus (the kidney’s filter). Sometimes this is temporary (short-term damage), while other times it is chronic (long-term damage). The exact cause for the kidney damage is different for each person and may even be due to several factors combined.

Microalbuminuria arises when GBM, a complex sieve, leaks an increased amount of albumin. The proposed mechanism is a combination of glomerular size enlargement, GBM thickening, mesangial expansion, and podocyte foot process effacement. Microalbuminuria can also occur via inadequate tubular reabsorption.

In contrast, albuminuria specifically refers to an abnormal excretion rate of albumin. Microalbuminuria refers to an abnormally increased excretion rate of albumin in the urine in the range of 30–299 mg/g creatinine.

stick test should therefore be referred to as albuminuria (or macroalbuminuria, to differentiate it from microalbuminuria) rather than proteinuria, since other proteins in the urine, such as globulins, light chains, and glycoproteins are not detected by dipstick testing. Besides macroalbuminuria, other terms