Diabetic Kidney Disease: Why Creatinine and Urine ACR Testing Matter
Posted 01 Jul 2026 | Source:

Diabetes is the most common cause of kidney failure, but this outcome is far from inevitable. The key to preventing it lies in detecting kidney involvement early, when treatment is most effective. Two simple, inexpensive tests make this possible: a blood test for creatinine (with eGFR) and a urine test for albumin, known as the urine albumin-to-creatinine ratio, or UACR. This article explains why both are essential for anyone living with diabetes.

Why diabetes harms the kidneys

The kidneys filter the blood through millions of tiny filtering units. In diabetes, persistently high blood sugar gradually damages these filters and the small blood vessels that supply them. Over years, this damage reduces the kidneys’ ability to filter and causes the filters to become leaky. The process is usually slow and silent, producing no symptoms until it is well advanced — which is exactly why testing matters.

The two tests, and why you need both It is a common misunderstanding that a single blood test is enough to check the kidneys in diabetes. In fact, the two tests measure different things, and each can be abnormal when the other is normal.

The blood test (creatinine and eGFR) tells us how well the kidneys are filtering overall. A rising creatinine or a falling eGFR indicates reduced filtering capacity.

The urine test (UACR) detects albumin, a protein, leaking into the urine. In diabetic kidney disease, the filters often begin to leak albumin before the eGFR falls at all. This means the urine test can detect kidney involvement at an earlier stage than the blood test — sometimes years earlier.

Because of this, checking only the blood test can give false reassurance. A person with diabetes can have a perfectly normal eGFR while already leaking albumin into the urine, signalling early kidney damage. Only by doing both tests do you get the complete picture.

What is a normal UACR, and what do raised levels mean?

The UACR measures the ratio of albumin to creatinine in a urine sample, which conveniently corrects for how dilute or concentrated the urine is. A normal result indicates little or no albumin leakage. A moderately raised result, historically called microalbuminuria, indicates early kidney involvement. A more substantially raised result, historically called macroalbuminuria, indicates more established damage.

An important practical point is that a single raised UACR should be confirmed, because temporary factors — such as a urinary infection, recent vigorous exercise, fever, or poorly controlled blood sugar on the day — can cause a transient rise. The test is usually repeated to confirm a persistent abnormality before drawing conclusions.

How often should people with diabetes be tested?

Current guidance recommends that most people with diabetes have both their eGFR and their UACR checked at least once a year. For those who already have evidence of kidney involvement, testing may be more frequent, as the trend over time guides treatment. If you have diabetes and have never had a urine albumin test, it is worth asking for one specifically, as it is sometimes overlooked.

Why early detection changes everything

The reason this testing matters so much is that early diabetic kidney disease responds well to treatment. When kidney involvement is detected early, several measures can slow or even partly reverse it: tighter control of blood sugar, careful control of blood pressure, and the use of specific kidney-protective medications that have been shown to reduce protein leakage and preserve kidney function.

Modern medications in this area have substantially improved the outlook for people with diabetic kidney disease in recent years.

Detected late, by contrast, diabetic kidney disease is much harder to control, and a proportion of people progress to needing dialysis or a transplant. The difference between these two paths often comes down to whether the problem was caught early — which depends entirely on testing.

The takeaway

If you live with diabetes, two simple tests once a year — a blood test for eGFR and a urine test for albumin — are among the most valuable things you can do to protect your kidneys. They are quick, widely available, and inexpensive, and they can detect a problem at a stage when something can still be done about it.

If you have diabetes and want to understand your kidney health, a nephrologist can review your eGFR and urine albumin results and advise on protecting your kidneys. A video consultation is a convenient way to start.