# Urine albumin-to-creatinine ratio (UACR): what the result compares

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A urine test that compares two measurements from the same sample, so a concentrated or dilute sample matters less.

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UACR compares the albumin concentration in a urine sample with the creatinine concentration in the same sample. Albumin is a blood protein that can pass into urine, and creatinine adjusts for how dilute the sample is. The ratio is reported in mg/g or mg/mmol, and the reference range printed on your report applies.

A urine result depends heavily on how much water was in the sample. The ratio exists to reduce that dependence, which is why the two numbers are reported together rather than albumin alone.

## What the test measures

Albumin is a protein made in the liver and normally kept in the blood by the glomeruli. Small amounts can pass into urine, and the amount can change when the filtration barrier is affected. Measuring albumin in a spot urine sample is simpler than collecting urine over a set period, but the concentration depends on how dilute the urine is.

Creatinine is used as the denominator because it is released from muscle at a fairly steady rate and passes into urine. Dividing albumin by creatinine gives a ratio that is less sensitive to hydration than albumin concentration alone. The result is calculated from two measurements on the same sample, not measured directly.

Some labs report the ratio from a spot sample; others ask for a timed collection. The two are not directly comparable, and the report says which was used.

## Why it may be ordered

- Alongside eGFR when kidney function is being assessed, because the two look at different things.
- When a urine dipstick or urine routine shows protein.
- To follow albumin loss over time, especially when a previous result has changed.
- As part of the assessment of people with diabetes or high blood pressure, where changes in the filtration barrier are a known concern.

UACR is usually read with eGFR, not instead of it. eGFR estimates filtration; UACR looks at what is passing through the filter. A clinician uses both to build a fuller picture.

## The unit on your report

| What you may see | Unit | What it reflects |
| --- | --- | --- |
| UACR, ACR, urine albumin/creatinine ratio, albumin-creatinine ratio | mg/g | Milligrams of albumin per gram of creatinine in the same urine sample. |
| UACR, ACR, albumin-creatinine ratio | mg/mmol | The same comparison on the SI scale, milligrams of albumin per millimole of creatinine. |
| Urine albumin, microalbumin | mg/L | The albumin concentration without the creatinine adjustment; this is not the ratio. |
| Urine creatinine | mg/dL or mmol/L | The denominator of the ratio, used to adjust for how concentrated the sample is. |
| Calculated | — | A note that the ratio was derived from two measurements on the same sample. |

## Why this page does not print a range

Reference ranges for UACR depend on the laboratory, the assay, the sample type, age, sex, pregnancy, and clinical context. Some labs print a single upper limit; others print ranges that differ by sex or by collection type. The unit matters too: a range printed in mg/g does not apply to a value reported in mg/mmol.

The range printed on the report that produced your value is the one that applies. Doctano keeps that printed range with the result and does not replace it with a general range from the internet. Read the value and the range in the unit the report itself prints.

## What a high value can mean

A higher ratio means more albumin relative to creatinine in that sample. It can be associated with changes in the kidney's filtration barrier, with diabetes, and with high blood pressure. It can also rise temporarily with fever, vigorous exercise, a urinary tract infection, or menstrual blood in the sample. Because the ratio divides by creatinine, a low urine creatinine can raise it without more albumin.

A single higher ratio does not confirm or rule out kidney disease, and a lower ratio does not rule it out either. Clinicians often repeat the test before drawing a conclusion, because sample-to-sample variation is common.

## What a low value can mean

A lower ratio usually means little albumin relative to creatinine in that sample. It is not usually interpreted on its own, and a very dilute sample can lower both measurements. A high urine creatinine can lower the ratio without any change in albumin. The report's range and the trend decide what the value means in context.

## What can move the value

- **Hydration and urine concentration.** A dilute or concentrated sample can move both measurements.
- **Exercise.** Vigorous activity before the sample can raise albumin temporarily.
- **Fever and infection.** A urinary tract infection or a fever can raise the ratio.
- **Menstruation.** Blood in the sample can affect the result.
- **Sample timing and type.** A spot sample and a timed collection are not directly comparable.
- **Medicines.** Some classes can change urine albumin or urine creatinine; a clinician can say whether a medicine is relevant.
- **Assay.** Different laboratories use different methods for albumin and creatinine.

## What to compare it with

eGFR is the closest comparison: it estimates filtration, while UACR looks at albumin passing the filter. Creatinine on the blood side and urea give context for kidney handling. A urine routine or dipstick, if on the same report, gives a rougher protein reading and should not be treated as the same measurement. The previous UACR from the same laboratory is the best comparison for a trend.

## How to see the trend

Doctano reads the ratio, its unit, and the reference range printed on the report. It keeps the range with the result, normalizes the marker name across labs, and places the value on the profile's timeline. Each point still opens the report it came from.

When one report uses mg/g and another uses mg/mmol, Doctano normalizes units for the timeline. Verify the value and the unit against the original report before treating a change as real, especially when the two results came from different laboratories.

## What this page is not

This page explains the test in general. It does not interpret your result, diagnose a condition, or recommend treatment. It is not medical advice. Verify the value and the unit against the original report, and discuss the result with a qualified professional.

## UACR questions

**What does the urine albumin-to-creatinine ratio compare?**

It compares the amount of albumin in a urine sample with the amount of creatinine in the same sample. Albumin is a blood protein that can pass into urine, and creatinine adjusts for how concentrated the sample is. The result is a calculated ratio, not a direct measurement of either substance.

**Why is creatinine in my urine report?**

Creatinine is used as the denominator of the ratio. It is released from muscle at a fairly steady rate and passes into urine, so it reflects how dilute the sample is. The urine creatinine is not the same as a blood creatinine result, and it is not a kidney function test on its own.

**Is UACR the same as a urine protein test?**

No. A urine protein dipstick gives a rough reading of total protein, while UACR measures albumin specifically and adjusts for urine concentration. The two are not interchangeable, and a report may include both. Read the name and the unit of the result you are looking at.

**Why might UACR be repeated?**

The ratio can vary from sample to sample with hydration, exercise, fever, infection, and the time of collection. Because of that variation, a single result may not reflect the usual pattern. Clinicians often repeat the test and read the trend, and the range printed on each report applies to that report.

## Limits

**This is not a diagnosis.** UACR is read with your eGFR, other results, your history, and the range printed on your report. Verify the value against the original report and discuss it with a qualified professional.

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