Urine albumin: what it is, what it tells you and why we test it

The urine albumin test, also called microalbuminuria, looks for albumin in your urine. Albumin is a blood protein that healthy kidneys hold back almost entirely. When more of it gets through, it is usually the earliest sign of kidney strain, years before the kidneys filter less.

Why we test it

Your kidneys filter your blood, but hold back useful proteins such as albumin. If more of it passes into your urine, and not for a passing reason, the kidneys’ filter has usually started to get damaged.

This often happens years before eGFR falls. And that is exactly the stage when protecting your kidneys works best.

It matters for your heart too. Albumin in the urine signals damage to small blood vessels, and is linked to a higher risk for the heart and arteries.

What it tells you, and what it does not

If it is high, your kidneys let more albumin through than normal. The most common causes are diabetes and high blood pressure.

But one high result is not enough: hard exercise, a fever, a urine infection or your period can raise it for a short while. That is why it is confirmed on a second sample.

And it does not show how well your kidneys filter: that is what eGFR is for. You can have albumin in your urine with a normal eGFR, and that is the best moment to catch it.

That is why it is read together with other tests:

Normal urine albumin levels

Rosa measures the ratio of albumin to creatinine in your urine, in mg/g. Below 30 is normal on many lab reports. From 30 to 300 albumin is moderately high, above 300 very high.

The ratio to creatinine corrects for how concentrated your urine is. So one sample is enough, ideally from your first urine of the morning.

Some reports use other units. In mg/mmol, 30 mg/g is about 3 mg/mmol. In mg/L or mg/24 h it is a different measure: go by the limit printed next to it.

In the Rosa report you also see your optimal range and what to do to reach it or stay in it.

What your result means

Find the row for your result, in mg/g. Which values should a doctor see? From 30 up; above 300, without putting it off.

If your urine albumin is high

What causes high urine albumin

The first three are temporary. That is why a high result is confirmed on a second sample.

Symptoms

Usually none. In small amounts, albumin in your urine cannot be seen and causes no discomfort: only the test finds it.

When a lot of it gets through, your urine can be very foamy and your ankles or eyelids can swell. If so, talk to your doctor.

High albumin: in your urine or in your blood?

Albumin in the blood, the test simply called albumin, says something about nutrition and your liver. Albumin in the urine is about your kidneys.

If your report says high albumin, check where. In the urine it is a signal about your kidneys; in the blood it usually just means too little water.

Albumin in the blood has a page of its own:

How to lower urine albumin

It depends on the cause, and it can often be done. Where to start:

What can skew the result

A few things raise the number for a while. It helps to know them before you collect the sample.

When to worry

Talk to your doctor if:

With Rosa, a urine albumin-to-creatinine ratio of 30 mg/g or more is always flagged to a doctor; above 300 with more attention. The test is usually repeated on another sample to confirm it.

Frequently asked questions

What is the difference between microalbuminuria and proteinuria? Proteinuria measures all the protein in your urine, microalbuminuria only albumin, even in small amounts. That is why microalbuminuria picks up kidney damage earlier.

My report gives it in mg/L or mg/24 h: how do I read it? They are different measures. In mg/L it is the concentration, which changes with how much you drank; in mg/24 h it is the amount over a whole day. Go by the limit printed next to it: Rosa uses the ratio to creatinine, in mg/g.

How do I collect urine for the test? Usually you need a sample of your first urine of the morning, taken midstream into a sterile container. Avoid hard exercise in the two days before and the days of your period, and follow your lab’s instructions.

Is high urine albumin serious? On its own it is not a diagnosis: it can rise for a short while after hard exercise or with a fever. If it stays high, your kidneys need protecting with your doctor, and the sooner you start the better.

How often should it be checked? For people who feel well there is no fixed rule: Rosa measures it once a year. If it is high, it is usually repeated on another sample and then checked again after about three months, or when your doctor says so.

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