Why Kidney Disease Is Found Late, and What Would Change That

The Centers for Disease Control estimates that about 35 million American adults have chronic kidney disease. That is roughly one in seven. As many as nine in ten of them do not know it. Among people with the most severe form short of dialysis, a large share are still unaware.

Those figures have not moved much in a decade. They are strange for a disease with a cheap, reliable, early test. The reasons say a lot about how preventive medicine actually works.

The organ does not complain

Kidneys have enormous reserve. A person can lose half of kidney function and feel nothing. Symptoms like swelling, fatigue, nausea, and itching appear late, often when function has fallen below 15 or 20 percent. By then the options are dialysis, transplant, or a slow decline.

Compare that to a heart, which produces chest pain, or a lung, which produces breathlessness. The kidney gives no warning that the patient can feel. The only warning is in the lab results.

The warning is in urine, not blood

Kidney function is usually tracked with a blood test for creatinine, converted into an estimated filtration rate called eGFR. That number is on nearly every routine metabolic panel, so most adults have one.

The problem is that eGFR falls late. The earliest sign of kidney damage, particularly the kind caused by diabetes and high blood pressure, is albumin leaking into urine. That happens years before eGFR moves. It is measured with a urine albumin to creatinine ratio, or uACR.

Guidelines have recommended a yearly uACR for every person with diabetes for over twenty years, and for people with hypertension for nearly as long. Actual testing rates in the US hover around 40 to 50 percent for people with diabetes and far lower for people with hypertension alone. The blood test gets ordered. The urine test does not.

Why the urine test gets skipped

Several small frictions add up.

It is a separate order. The metabolic panel is a single checkbox that most clinicians tick by habit. The uACR is a second checkbox on a different part of the form, and it requires a urine cup, which means a visit to the bathroom before the patient leaves.

It has been rebranded several times. Microalbumin, albumin to creatinine ratio, uACR, urine albumin. The names confuse ordering systems and patients alike.

There has been no penalty for skipping it. Quality measures for diabetes care have long emphasized A1C, blood pressure, and eye exams. Kidney testing was added to major quality programs only in the last few years.

And the result, when it is abnormal, has historically led to a conversation rather than a prescription. That has changed. There are now several drug classes that slow kidney decline in people with albuminuria, including SGLT2 inhibitors and newer agents. An early positive result now has a clear next step, which changes the calculus of looking.

What would change it

Three things are already in motion.

Bundled testing. Some health systems have made the uACR part of the default diabetes order set, so the clinician has to opt out rather than in. Testing rates in those systems rise sharply.

Quality measures. The Kidney Health Evaluation measure, adopted by national quality programs, scores health plans on whether people with diabetes get both an eGFR and a uACR each year. Plans are now paid partly on it.

Home testing. A uACR can be run on a strip at home, with or without a phone app that reads the color. Mail in kits return a lab result. Home testing removes the bathroom trip and the separate order. The result still needs to be confirmed and acted on by a clinician, but it gets the number into the conversation. See kidney health urine tests for how the home versions work.

What you can do

If you have diabetes or high blood pressure, ask for a uACR by name at your next visit. Ask what the result was. Under 30 mg/g is normal. If it is over 30, ask when it will be repeated.

If you have a parent or sibling with kidney disease, ask whether you should be tested.

If you have neither, a standard dipstick protein pad now and then is enough. A persistent 1+ or higher is the signal to get the real test.

The disease is found late because nobody looks early. Looking early is cheap. That is the whole story.