Last year my 17 year old, who has had diabetes for three and a half years and competes in two varsity sports, had a slightly high 24-hour microalbumin level (42.5mg) so the test was repeated after my son ceased exercising for five days, and the result was within normal limits. He is now in the process of switching him from a pediatric to an adult endocrinologist who did a 24 hour urine microalbumin and a creatinine clearance. The creatinine clearance was 152 but everything else was within normal limits. Serum creatinine was 1.1, and my son had not been vigorously exercising the day of or the day before the 24 hour test.

Should we be concerned with the elevated creatinine clearance in light of my son’s exercise regimen? Is microalbumin a more precise or better test for early warning signs in the search for kidney disease?

You should talk with your son’s physician, but in general, for a physically/developmentally mature person with type 1 diabetes, I would heed usually recommendations that urinary microalbumin be screened annually (perhaps along with screening for other complications/co-morbidities such as a cholesterol profile, thyroid levels, screen for celiac disease, and a formal dilated eye exam by an ophthalmologist).

Your note is a bit unclear, but I presume that your son’s 24 hour microalbumin excretion was 42.5 mg (milligrams) per 24 hours (normal less than 30). But there are other ways to express this: microalbumin concentration per minute which usually is expected to be less than 20 micrograms per minute. A number of other situations can lead to increased urinary albumin excretion including exercise, illness, “stress”, and other kidney problems.

I would consider a serum creatinine level of 1.1 mg/dL in a husky, athletic, otherwise well 17 year adolescent, regardless of having diabetes, as being normal. But other issues besides kidney problems can cause the creatinine to rise a little. One common thing that comes to my mind immediately in an athletic male teen, would be the use of protein supplements such as creatine and others. Creatinine is a breakdown product of protein along with creatine (don’t become confused about creatine vs. creatinine) and could be increased if there were increased protein loads through the digestive system.

DS
Additional comments from Dr. Stuart Brink:

Microalbumin testing is more sensitive and usually shows abnormalities far earlier than total protein or creatinine clearance testing. It is a misnomer since the test does not test small albumin but only has much greater sensitivity for detecting small amounts of albumin being leaked. Normal values are usually less than 7. Some would say less than 20 or 30. Increased activity sometimes causes protein leakage as does illness during collection. Sometimes high levels of glycemia during the collection period would also be associated with protein leakage. So we usually recommend several specimens. We usually recommend overnight rather than 24 hour specimens so that we minimize any daytime activity association. You should go back and discuss this with your son’s diabetologist and map out a plan to get sequential testing to see if this is a real abnormality or not. Annual testing is the standard recommendation for microalbuminuria.

Make sure that your son is not taking extra protein supplements and that total protein intake is as low as possible. Consult with a dietitian who knows about protein needs of teens and young adults who have diabetes and may have the beginnings of kidney problems. Smoking may increase protein leakage just as high glucose levels. Cutting back protein intake, especially protein intake from animal sources, is often very helpful. Not using steroids and not taking any protein supplements of any kind would also be very wise.

The most important factor is improving hemoglobin A1c levels and day to day glucose control. If protein levels remain abnormal, most would recommend more strict protein restriction, maximizing glucose control and adding one of the ACE inhibitors.

SB