Albumin/Creatinine Ratio, 24 HR Urine

Albumin/Creatinine Ratio, 24 HR Urine – Austin, TX

Albuminuria is defined as an abnormal loss of albumin in the urine. Because of its small molecular size, albumin is one of the first proteins to pass through the kidneys into the urine when kidney damage develops. The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guideline on the evaluation and management of chronic kidney disease (CKD) has defined three categories of albuminuria when measuring albumin excretion through either a 24 hour test (reported as mg per 24 hour) or an albumin to creatinine ratio (reported as mg/g or mg/mmol):

A1 or normal albuminuria: <30 mg/24 hr or mg/g (<3 mg/mmol)

A2 or moderately increased: 30-300 mg/24 hr or mg/g (3-30 mg/mmol)

A3 or severely increased: >300 mg/24 hr or mg/g (>30 mg/mmol)

These categories, along with measurement of estimated glomerular filtration rate (eGFR), are used to stage the severity of the CKD.Creatinine is produced during skeletal muscle contraction via the breakdown of creatine phosphate.

Creatinine is excreted by the kidneys – its concentration in the bloodstream is an indicator of renal function. In the absence of kidney disease, the urinary creatinine is excreted in rather constant amounts and represents glomerular filtration and active tubular excretion of the kidney.