November 8, 2003
Question from what I can find on the Internet normal ranges would be microalbumin: 0-19 mg/l, creatinine:
My teenager, who has had type 1 diabetes less than five years, recently had a random urine test which showed a microalbumin of 93.6 mg/l, a creatinine of 199.3 mg/dl, and an albumin/creatinine ratio of 47.0 mg/g. I have called the family doctor, pediatric endocrinologist and the lab running the test trying to understand these numbers, but evidently there are no reference ranges noted at the lab, so all anyone can say is that 47.0 is high. A 24 hour urine sample is ordered, and I understand that it is not unusual to have an occasional abnormal result due to exercise, infection and other factors. Any clarification you could give us would be greatly appreciated.
You need to talk to the doctor who ordered the test as he/she can make more specific recommendations. In general, pediatric and adolescent values are considerably lower than in adults. However, there is some discrepancy in the literature and no general consensus yet about what level would require intervention. It is also important to get family history about blood vessel, kidney and blood pressure problems since this helps to define individual risk (presumably genetic). Not smoking is critical. Most importantly, the higher the glucose values and the longer duration of these highs (day to day blood glucose ranges and hemoglobin A1c levels), the higher the likelihood of kidney problems.
The late stage kidney problems require transplantation or kidney dialysis. Hypertension is an earlier possible signal of kidney problems (and other issues). Protein leakage is another marker of kidney problems, but non-specifically. The most sensitive assays are a misnomer and called microalbumin. It has nothing to do with little albumin but with the sensitivity of the assays to detect small amounts of protein (albumin) leakage. Exercise and infection certainly are associated with microalbuminuria.
One of the reasons many of us do overnight instead of 24 hour microalbumin measurements is an effort to decrease the effects of exercise bursts. Very conservative levels include microalbumin less than 20-30 ugm/min corrected to 1.73 meter squared. When trying to establish normal values in a pediatric population without diabetes, however, the 97th percentile cut off is usually in the range of around 7 so it is reasonable to be wary of values in the 7-30 range. Calculations using microalbumin/creatinine ratio allow some groups to use spot urine screening instead of timed urine. Albumin excretion rate is another way of looking at this data as well. All provide similar measurements. All need to be done several times to see if a pattern or trend exits.
Improved blood glucose control is still the best way to prevent such problems or to have a chance to improve abnormal values. Being aggressive with blood pressure lowering medications is also helpful. Most commonly used are medications called ACE inhibitors which can be used quite safely in older children and teens. In fact, almost any blood pressure lowering medication, even when blood pressure per se is not abnormal, seems to help lower microalbuminuria in several studies the past few yeas. So go back to your teen’s diabetes team and have them explain these findings and map out a plan to recheck several times before making any therapeutic decisions.