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Table of contents
Urine albumin creatinine ratio definitionHow to take a urine sample?Albumin in urine – what does that mean?CKD stages – what is normal albumin creatinine ratio?What is albumin creatinine ratio? Step-by-step ACR calculatorAlbumin creatinine ratio calculator in practiceFAQsAre you looking for a tool to determine the level of albuminuria? This albumin creatinine ratio calculator calculates the ACR (albumin-to-creatinine ratio).
Below, you'll find some useful information on what microalbumin is, urine microalbumin creatinine ratio use, the classification of the CKD stages, and more!
This tool mostly concentrates on chronic kidney disease. To find the cause of acute kidney injury, go to our FEUrea or FENa calculators.
Urine albumin creatinine ratio definition
Albumin-to-creatinine ratio serves as a detector of elevated protein levels in the urine (albuminuria), the first test to estimate kidney function. To perform these calculations, the lab needs just one sample of your urine. A 24-hour collection, as required for calculating the protein-creatinine ratio, is not necessary.
💡 Want to find out more about your albumins? Try yet another useful tool; the albumin globulin ratio calculator.
How to take a urine sample?
On average, health care professionals recommend taking the sample from the first urination in the morning, after a proper washing of the genitals. The sample should be taken from the middle part of the micturition and needs to be collected into a box and then quickly delivered to the lab. 🧪
We calculate ACR by dividing urine microalbumin concentration in milligrams by the creatinine concentration in grams. You can find the interpretation of the results in the paragraphs below.
Albumin in urine – what does that mean?
Albuminuria, along with a low GFR (glomerular filtration rate) and a high BUN (blood urea nitrogen), are signs that the kidneys are not functioning well. Albumin is a small protein typically present in the blood. It helps maintains the proper osmotic pressure and transports medications, hormones, etc., throughout the body.
The presence of albumin in the urine is called albuminuria or sometimes proteinuria. Measurement of urine albumin is an important tool for diagnosing kidney disease and monitoring kidney disease progression. 🔬People at risk of kidney disease and increased ACR are those with:
- Diabetes;
- High blood pressure;
- Heart disease; and
- A family history of kidney disease.
They should all check their ACR regularly.
💡 You might also find our BUN creatinine ratio calculator helpful.
CKD stages – what is normal albumin creatinine ratio?
CKD, also known as Chronic Kidney Disease, is one of the main conditions leading to albuminuria. CKD is a process that slowly progresses throughout the years, decreasing the function of kidneys. 🥼 The best way to classify CKD is by GFR (glomerular filtration rate). In our case, the CKD stages can also be classified by the level of albuminuria.
Category | ACR (mg/g) | Terms |
---|---|---|
A1 | <30 | Normal to mildly increased |
A2 | 30-300 | Moderately increased |
A3 | >300 | Severely increased |
What is albumin creatinine ratio? Step-by-step ACR calculator
To use this ACR calculator, you need to have the albumin and creatinine concentration levels found in the urine. Albumin's unit is most probably mg/dL,
whereas you might get mg/dL
or mmol/L
for creatinine.
The formula for ACR is:
ACR = Albumin / Creatinine
and the unit for ACR is mg/g
.
Albumin creatinine ratio calculator in practice
Let's work on this load of theory in practice. Annie is a 63-year-old who has had blood tests every year as a means of prophylaxis. 🩸Those tests included a urine test to check for early signs of a complication related to her diabetes. Her GP (general practitioner) found some basic parameters, like glucose, white blood cells, and finally, albumin and creatinine.
This year though, there was some worry with the latter two levels. The physician quickly calculated the ACR using this albumin creatinine ratio calculator.
Albumin in urine: 8 mg/dL
Creatinine: 110 mg/dL = 0.11 g/dL
ACR = Albumin/Creatinine
ACR = 8/0.11 = 72.7 mg/g
The table in the paragraph above shows that a result between 30 and 300 mg/g means the level of albuminuria is moderately increased, and the patient is placed in category A2 of CKD stages.
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How to calculate ACR?
Let's calculate the albumin-to-creatinine ratio in the easiest way possible:
Find the albumin level in urine in mg/dL – e.g., 10 mg/dL.
Write down the creatinine concentration in g/dL – e.g., 150 mg/dL = 0.15 g/dL.
Use the equation:
ACR = Albumin/Creatinine
ACR = (10 mg/dL) / (0.15 g/dL)
ACR = 66.7 mg/g
Here's the result – your ACR is equal to 66.7 mg/g. This value is classified as moderately increased.
What is CKD stage A2?
Chronic kidney disease (CKD) can be categorized into different stages according to the glomerular filtration rate (GFR) and albuminuria (albumin-to-creatinine ratio – ACR). We can talk about:
- GFR categories (G1-5); and
- ACR categories (A1-A3).
Category A2 describes moderately increased albuminuria, between 30 and 300 mg/g (3-30 mg/mmol).
How can we measure the ACR?
We can measure the albumin-to-creatinine ratio (ACR) with a simple urine test, which has the following features:
- ACR screens for kidney diseases.
- You don't need to prepare for this test.
- According to multiple studies, the ACR is as accurate as a 24-hours albumin testing!
How do we convert creatinine units?
We can convert creatinine to mmol/L or mg/dL. Here are the conversion factors:
1 mmol/L = 0.056 mg/dL
; and1 mg/dL = 18 mmol/L
.