Methods and compositions for the detection and diagnosis of renal disease and periodontal disease

A method for diagnosis and treatment of acute kidney injury in a subject comprising detecting an amount of a cystatin B polypeptide, comparing the amount of the cystatin B polypeptide to a control sample or control standard, wherein the cystatin B polypeptide comprise a sequence as set forth in SEQ ID NOs:2, 3, 5, 6, 7, 11, 12, or combinations thereof diagnosing the subject with acute kidney injury where elevated levels of the cystatin B polypeptide compared to the control sample or control standard are present, and treating the subject for acute kidney injury, wherein the treating comprises surgery for obstructive nephron/ureteroliths, chemotherapy for renal neoplasia, dietary management, enteric phosphate binders, administration of antiproteinurics, administration of antihypertensives, fluid therapy, management of acidosis, administration of diuretics, dialysis, correction of electrolyte abnormalities, administration of antiemetics, administration of antacids, or administration of recombinant erythropoietin.