The presence of blood in the urine. Hematuria may be gross hematuria (visible to the naked eye) or microscopic hematuria (detected by dipstick or microscopic examination of the urine).

Increased levels of protein in the urine.

A degree of kidney failure severe enough to require dialysis or kidney transplantation for survival characterized by a severe reduction in glomerular filtration rate (less than 15 ml/min/1.73 m2) and other manifestations including increased serum creatinine.

The presence of immunoglobulin A deposits in the glomerulus.

Increased numbers of mesangial cells per glomerulus, defined as more than 3 nuclei fully surrounded by matrix in one or more mesangial areas, not including perihilar region, on a standard 3-micron-thick tissue section, best evaluated on periodic acid-Schiff (PAS) stain.

The presence of chronic increased pressure in the systemic arterial system.