If you have diabetes, a kidney check should usually include both a blood test for estimated glomerular filtration rate (eGFR) and a urine albumin-to-creatinine ratio (UACR). These tests look for different signs of kidney trouble, so together they give a more complete picture of how kidneys and blood sugar may be affecting your health. An abnormal result is a reason to follow up, not automatically a diagnosis.
How kidneys and blood sugar screening works
The eGFR is calculated from a blood creatinine result and estimates how well your kidneys filter waste. A persistently low eGFR—below 60 mL/min/1.73 m²—is one marker of chronic kidney disease (CKD). But eGFR can be normal, or even high, in early kidney disease.
UACR measures albumin, a protein, in your urine in relation to creatinine. An elevated result can signal kidney damage before eGFR falls. A UACR of 30 mg/g or more (about 3 mg/mmol) is considered elevated. The two results are used together because kidney damage can show up as albumin in urine, reduced filtering function, or both. A reassuring result on one test does not make the other unnecessary.
When screening should start
The American Diabetes Association (ADA) and Kidney Disease: Improving Global Outcomes (KDIGO) recommend regular testing with both eGFR and UACR. Their timing is broadly aligned: for type 2 diabetes, screening begins at diagnosis and is generally repeated annually. For type 1 diabetes, it generally begins five years after diagnosis and is repeated annually.
That difference reflects when kidney disease may become detectable: type 2 diabetes can be present for some time before diagnosis, while kidney complications in type 1 diabetes usually emerge later. Annual testing is a routine check, not a prediction that you have kidney disease. If CKD is already present or risk is higher, your clinician may recommend more frequent monitoring.
In the UK, NICE guidance also emphasizes checking kidney function and urine albumin in people with diabetes. It gives specific instructions for confirming some urine results: an ACR from 3 to 70 mg/mmol should be checked in a subsequent early-morning urine sample. NICE says an initial result of 70 mg/mmol or more does not need that repeat sample for confirmation of proteinuria. Local guidelines and reporting units can differ, so ask how your laboratory reports UACR—commonly mg/g in the United States and mg/mmol in the UK and parts of Europe.
Why an abnormal result may need repeating
Creatinine, eGFR and urine albumin measurements can vary. A single unusual result may not reflect a lasting change. CKD is generally defined by a kidney abnormality that persists for more than three months—for example, eGFR below 60 or UACR of at least 30 mg/g. Your clinician may repeat a test sooner to check the finding, then use results over time to determine whether it is persistent.
This is why “abnormal” and “chronic kidney disease” are not interchangeable. Repeat testing helps distinguish a lasting pattern from a one-off result, and it can guide decisions about monitoring or care. NICE’s early-morning urine recommendation is one example of a guideline-specific step; ADA and KDIGO also base CKD identification on persistence, not just a single reading.
What to do with your results
If you have diabetes, check whether your recent tests included both eGFR and UACR. If only a blood test was done, ask whether a urine albumin test is also due. If a result is outside the usual range, ask what it means in your case, whether it needs repeating, and when. Your clinician can interpret the numbers alongside your previous results and other health information. Do not diagnose yourself from one result; seek clinical advice if you are concerned or unsure what follow-up is planned.
