June 2, 2009
Question from Pinnacle, North Carolina, USA:
What does it mean when your laboratory findings find 78 mg/g creatinine (urine microalbumin)? Is that good? What is the normal range? What does that mean?
The random urine for albumin to creatinine ratio has generally replaced the 24-hour urine for albumin because of its ease of use in the clinic (no more jugs and no more long urine collections on ice) and its performance. It gives levels that are generally similar to the 24-hour urine tests. Since it is a ratio, the units for the result are in mg albumin per gram of creatinine. Most laboratories use a cutoff of 30 for the upper limit of normal. Levels above this are considered elevated. There is a large amount of variability in the amount of urine albumin excreted by any one person. Therefore, if an elevated level comes back for the first time, it should be repeated to determine if the elevation is persistent. If it were, this condition would be termed microalbuminuria. Microalbuminuria has been shown to be a risk of the development of kidney disease, especially in type 1 diabetes. It probably is in type 2 diabetes, too, but it is also a risk for vascular disease, such as atherosclerosis. The recommendations for treatment of microalbuminuria involve the use of an ACE inhibitor or an angiotensin receptor antagonist. These agents lower albumin excretion and have been shown in clinical trials to have kidney protection effects. They are traditionally blood pressure lowering medications. Part of their benefit is in lowering blood pressure, but there are some specific effects that are probably specific to effects within the kidney. The albumin to creatinine ratio should be followed every year and also after instituting therapy with one of the above agents. The goal is to bring the albumin level in the kidney back to normal. Blood pressure and blood sugar control are also very important.