Kidney Test Results Explained: Creatinine, eGFR, Albumin
What creatinine, eGFR and urine albumin (ACR) on your lab report mean, how KDIGO stages kidney disease and how often guidelines suggest checking them.
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Your lab report lists creatinine and eGFR, maybe a urine albumin result, and next to each a range that differs between labs. This article explains what each number measures and how often it is usually rechecked. It also shows how the international KDIGO guideline uses them to define and stage chronic kidney disease (CKD). You can keep the reports in a folder or in Sam's Health Vault, your own copy for your own use, not linked to an electronic patient record, where Sam takes values such as creatinine and eGFR from a photo or PDF once you consent.
What does creatinine measure?
Creatinine is a waste product from your muscles that the kidneys filter out of the blood. How much you make depends on your muscle mass. Blood creatinine only rises once the kidneys are considerably damaged. So on its own it is not suited to finding early kidney disease, notes the central lab at Ulm University Hospital.
The kidneys are not the only influence. Heavy physical work or a very meat-heavy meal just before the test can push it above the range in healthy kidneys. In people bedbound for a long time, it can stay in range even with clearly reduced kidney function. And with age, creatinine stays almost the same while filtering declines, because muscle mass falls too.
Labs report creatinine in mg/dL or in umol/L. 1.0 mg/dL is about 88 umol/L. Ranges depend on age and sex. The Ulm lab gives 45 to 84 umol/L for adult women and 59 to 104 umol/L for men. Labs also use different methods, so the range that counts is the one printed on your own report.
What is eGFR, and why is it an estimate?
eGFR stands for estimated glomerular filtration rate: how much blood your kidneys filter each minute. It is not measured directly. The lab calculates it with a formula from your creatinine, age and sex. The unit ml/min/1.73 m2 means the result is scaled to a standard body surface area.
Because creatinine tracks muscle mass, KDIGO notes that a creatinine-based eGFR can mislead at the extremes of body build. Sometimes that estimate is less accurate and a decision depends on it. For those cases the guideline recommends an equation that adds a second blood marker, cystatin C.
Kidney function declining with age is normal. Especially over 70, reduced kidney function is not necessarily caused by disease, notes the German GP guideline's patient leaflet.
What does urine albumin (ACR) tell you?
Albumin is a protein. The German GP guideline calls the amount in urine the other important kidney value next to eGFR. KDIGO says to test both in people at risk of or living with CKD.
Reports usually show the albumin-to-creatinine ratio, or ACR. It sets the albumin against the creatinine in the same urine sample, in mg/g or mg/mmol. For the first test, KDIGO prefers a first-morning midstream sample. A result of 30 mg/g or more from a random sample should be confirmed with a first-morning sample.
Per KDIGO, blood in the urine, a period, exercise and a urinary infection with symptoms can make the ratio falsely high.
When do kidney results count as chronic kidney disease?
KDIGO defines CKD as abnormalities of kidney structure or function, present for at least three months, with implications for health. Either is enough: an eGFR below 60, or a marker of kidney damage such as an ACR of 30 mg/g (3 mg/mmol) or more.
One abnormal result is not enough. The guideline says not to assume chronic disease from a single eGFR or ACR. The cause could be a recent acute kidney injury. As evidence of duration, it lists earlier results and repeat tests within and beyond the three months, among other things. That makes older lab reports useful to your doctor.
CKD is classified by cause, GFR category (G1 to G5) and albuminuria category (A1 to A3):
| Category | eGFR (ml/min/1.73 m2) | KDIGO term |
|---|---|---|
| G1 | 90 or more | Normal or high |
| G2 | 60 to 89 | Mildly decreased |
| G3a | 45 to 59 | Mildly to moderately decreased |
| G3b | 30 to 44 | Moderately to severely decreased |
| G4 | 15 to 29 | Severely decreased |
| G5 | under 15 | Kidney failure |
| Category | Urine ACR | KDIGO term |
|---|---|---|
| A1 | under 30 mg/g (under 3 mg/mmol) | Normal to mildly increased |
| A2 | 30 to 300 mg/g (3 to 30 mg/mmol) | Moderately increased |
| A3 | over 300 mg/g (over 30 mg/mmol) | Severely increased |
KDIGO adds that G1 and G2 only count as CKD when there are other signs of kidney damage. An example: a report shows an eGFR of 52 and an ACR of 45 mg/g. In the tables, that is G3a and A2. Whether it is CKD depends on the course over at least three months, and that is for your doctor to judge.
How often should kidney function be checked?
For people with CKD, KDIGO says to check urine albumin and eGFR at least once a year. Those at higher risk of progression should be checked more often when the result will influence decisions about your care. The German GP guideline (DEGAM, 2024) proposes its own figures. It says it follows the UK NICE guideline and, for practical reasons, sits somewhat below KDIGO.
These are the guide figures for checks per year, shown as A1 / A2 / A3:
| Category | KDIGO 2024 | DEGAM 2024 |
|---|---|---|
| G1 | 1 / 1 / 3 | up to 1 / 1 / 1 or more |
| G2 | 1 / 1 / 3 | up to 1 / 1 / 1 or more |
| G3a | 1 / 2 / 3 | 1 / 1 / 2 |
| G3b | 2 / 3 / 3 | up to 2 / 2 / 2 or more |
| G4 | 3 / 3 / 4 or more | 2 / 2 / 3 |
| G5 | 4 or more in each | 4 / 4 or more / 4 or more |
For the example above, G3a with A2, that is twice a year under KDIGO and once under DEGAM. You agree the schedule with your doctor, and with a kidney specialist where needed.
Results vary from test to test, for biological reasons and because of the measurement itself. KDIGO says the first step after an unexpected change is to repeat the test. Whether a change needs looking into, including after a new medicine, is for your doctor to judge. Mention any change that stands out to you, even a small one.
Can Sam read a urine albumin result?
Not as a named value. Sam knows 33 lab values by name, among them creatinine, eGFR, urea, potassium, sodium, calcium and hemoglobin. The urine ACR is not one of them. If it sits in the values table of a lab report you add, it can be taken over once you consent, with the range if one is printed next to it. Whether that works depends on how your report is laid out.
Sam does not tell urine values apart from blood values. A row such as "Creatinine, urine" and some ways of printing the ratio, such as "Albumin/Creatinine", are saved as creatinine. When two reports are compared, Sam can then set them against your blood creatinine if both carry the same unit. Check such rows on the saved report and do not rely on the comparison for them.
Before saving, you check every row and can correct the name, value and range. Correcting the name does not always change which value the row is filed under. For kidney values Sam converts no units and sets no range of its own. Where your report prints a range, Sam shows whether the value sits inside it. If a value is printed in different units on two reports, Sam does not compare it.
What to bring to a kidney check-up
The German GP guideline's patient leaflet says check-ups cover blood and urine results, blood pressure and your medicines. When needed, your doctor refers you to a kidney specialist (nephrologist).
- Earlier lab reports, including ones from other clinics or a hospital. How to ask for copies is covered in getting a copy of your medical records.
- An up-to-date list of everything you take, including over-the-counter and herbal products and supplements. KDIGO asks clinicians to review these, and the German GP guideline proposes a medication review at least once a year. See what to put on a medication list.
- Notes on the days before a blood or urine sample: heavy physical work, exercise, a very meat-heavy meal, a period or a urinary infection.
- New symptoms since your last visit, such as swollen legs or itching.
- Your questions: Which G and A category am I in? When is my next check? Does any of my medication need adjusting to my kidney function?
Some over-the-counter products, especially certain painkillers, can harm the kidneys, so check with your clinic before taking them. The German patient leaflet also advises telling every doctor you see that you have kidney disease. KDIGO notes that people with CKD often see several specialists, and keeping appointments and records for several conditions takes some planning.
In Sam, your medicines go in the medication list. The medication catalog is a selection, not a recommendation. Picking an entry prefills a pack strength, and you check and change strength and rhythm to match your plan. Whether a medicine needs adjusting to your kidney function is your doctor's decision. Sam does not check interactions. Symptoms such as leg or ankle swelling go in the symptom diary, one entry per symptom per day. For a general list, see the doctor appointment checklist for a chronic condition.
When not to wait for the next check-up
Early CKD usually causes no symptoms, according to the NHS and the German health information service IQWiG. Some signs still should not wait for a routine visit. For sudden or severe trouble breathing, chest pain or confusion, call your local emergency number (112 in the EU, 999 in the UK, 911 in the US).
For clearly less urine than usual, new swelling, breathlessness when you lie down, rapid weight changes, ongoing vomiting or diarrhea, or blood in your urine, ask for an urgent appointment with your doctor today. For other new symptoms, contact your doctor soon. Do not wait for it to pass. Out of hours, use your local urgent care line, such as NHS 111 in the UK. You can log blood in urine in the symptom diary, but Sam does not interpret the entry medically. It is a reason to see a doctor. What else Sam keeps for this condition is on the chronic kidney disease page.
Keep kidney lab reports and medicines ready in Sam
You arrive at the check-up with your reports and your medicines in one app, instead of hunting for separate sheets.
- Instead of a folder: in the Health Vault, Sam takes values such as creatinine, eGFR, urea, potassium and hemoglobin from a photo or PDF once you consent. You check them before saving.
- Instead of comparing two printouts: Sam compares your last two reports and shows up to three values that changed most. Where the report prints a range, you see whether the value sits inside it.
- Instead of a paper list: the medication list holds long regimens, with one notification per intake time.
Sam does not know urine albumin as a value of its own, saves urine creatinine as creatinine and does not check interactions. More on the chronic kidney disease page.
Try Sam for freeSam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any disease or health condition. Always consult qualified professionals for medical decisions.
Related reading
- Low eGFR: what to do after a high creatinine result
- Why was I referred to a nephrologist? What to expect
- Medication list for your doctor: what to include
- Doctor appointment checklist for a chronic condition
- Getting a copy of your medical records when changing doctor
- Managing multiple conditions: appointments and records
Sources
Updated: October 2026
- KDIGO: KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney International 2024;105(4S):S117-S314 (definition and Tables 1 to 3, Practice Points 1.1.1.1, 1.1.3.1, 1.1.3.2, 1.3.1.1 to 1.3.1.3 with Table 16, Recommendation 1.2.2.1, Practice Points 2.1.1 to 2.1.3 with Figure 13, Practice Points 4.1.3, 4.2.1 and 4.3.1)
- DEGAM/DGfN: S3 guideline on chronic kidney disease not requiring dialysis in primary care, long version (AWMF 053-048, version 2.0, 2024; definition section 4.1.1, monitoring pp. 116-117; German)
- DEGAM: Short version, care in established CKD (version 2.0, 2024; monitoring frequency, medication review; German)
- DEGAM: Patient information, CKD stages 1-3 and stages 4-5 (version 2.0, 2024, with the German kidney patients' association; German)
- NHS: Kidney disease (last reviewed 22 March 2023) and Acute kidney injury (last reviewed 11 March 2026)
- IQWiG (gesundheitsinformation.de): Chronic kidney disease (updated 14 August 2024; German)
- Ulm University Hospital, Central Clinical Chemistry: Creatinine test catalogue entry (revision 30 October 2020; influencing factors, units, reference ranges; German)
More on Chronic Kidney Disease
Frequently Asked Questions
What is a normal eGFR?+
KDIGO calls an eGFR of 90 ml/min/1.73 m2 or more normal or high, and 60 to 89 mildly decreased. Neither counts as chronic kidney disease unless there are other signs of kidney damage. An eGFR below 60 for at least three months meets the definition. Kidney function normally declines with age, but a lower number can also have another cause. Your doctor reads it together with your earlier results and your urine test.
Why might my creatinine be high?+
Creatinine comes from muscle, so it depends on muscle mass. Heavy physical work or a very meat-heavy meal shortly before the test can push it above the range even in healthy kidneys. One raised result is not a diagnosis: KDIGO looks at the course over at least three months. Have your doctor look at a raised result anyway. Whether and when to repeat the test is their call. What your doctor checks after an abnormal result is covered in low eGFR: what to do after a high creatinine result.
What does the urine albumin-to-creatinine ratio (ACR) mean?+
The ACR compares the protein albumin in your urine with the creatinine in the same sample. Next to eGFR it is the second core kidney test. KDIGO groups it as A1 (under 30 mg/g, under 3 mg/mmol), A2 (30 to 300 mg/g) and A3 (over 300 mg/g). A period, exercise, blood in the urine or a urinary infection with symptoms can make it falsely high.
When do kidney results count as chronic kidney disease?+
KDIGO defines CKD as abnormalities of kidney structure or function present for at least three months, with implications for health, such as an eGFR below 60 or an ACR of 30 mg/g or more. The guideline says not to assume chronic disease from a single abnormal result, because it could reflect a recent acute kidney injury. That is a reason to take an abnormal result to your doctor rather than wait and see.
How often should kidney function be checked?+
In people with CKD, KDIGO says to check eGFR and urine albumin at least once a year, and more often when the risk of progression is higher and the result will influence decisions about your care. The guide figures run up to four or more times a year depending on the stage. The German GP guideline (DEGAM) proposes somewhat lower figures. Your care team agrees the schedule with you.
What do G3a and A2 on my results mean?+
G3a means an eGFR of 45 to 59 ml/min/1.73 m2, and A2 a urine ACR of 30 to 300 mg/g (3 to 30 mg/mmol). The letters come from the KDIGO system, which grades kidney function and albumin separately. What the combination means for your check-ups is a question for your doctor.
Can Sam read my urine albumin result?+
Not as a named value. Sam knows 33 lab values by name, including creatinine and eGFR, but not the urine ACR. If the row sits in the values table of a lab report you add, it can be taken over once you consent. Urine creatinine and some ways of printing the ratio, such as Albumin/Creatinine, are saved as creatinine, though. Check such rows before saving and again on the saved report.
What should I bring to a kidney check-up?+
Earlier lab reports, an up-to-date medication list that includes over-the-counter and herbal products, notes on the days before the sample, any new symptoms and your questions. Some over-the-counter products, especially certain painkillers, can harm the kidneys, so check with your clinic before taking them.