Kidney tests for people with diabetes

The two main tests

Guidelines from KDIGO and the American Diabetes Association recommend using both of these tests together, because each can show changes the other misses.

Urine ACR: looking for albumin

Healthy kidney filters keep albumin in the blood. When diabetes damages the filters, small amounts of albumin start to leak into the urine. This is often the first sign of kidney changes in diabetes, sometimes years before eGFR falls.

The ACR test compares albumin with creatinine in the same urine sample. This corrects for how concentrated or dilute your urine is, so a single small sample is enough. An ACR of 3 mg/mmol (30 mg/g) or more is considered raised. KDIGO groups results into three categories: A1 below 3 mg/mmol, A2 from 3 to 30 mg/mmol, and A3 above 30 mg/mmol. See CKD stages for the full table.

ACR can rise for a short time for reasons that have nothing to do with lasting kidney damage, including:

• hard exercise in the day or so before the test
• a fever or infection, including a urine infection
• menstruation
• very high blood sugar or very high blood pressure at the time

So a raised ACR is usually repeated over the following weeks to months to confirm it. A standard urine dipstick is not a substitute, because it can miss small amounts of albumin.

Creatinine and eGFR: how well the kidneys filter

Creatinine is a waste product from the muscles. The kidneys normally clear it from the blood. The lab measures creatinine and then uses a validated equation, which also takes your age and sex into account, to calculate an eGFR (estimated glomerular filtration rate).

A creatinine result on its own does not show whether someone has kidney disease. Creatinine depends partly on muscle mass, and reference ranges vary between labs, by age and by sex. Always use the range printed on your own report. An eGFR below 60 mL/min/1.73m² that lasts more than three months is one of the signs doctors use when assessing CKD. Read the creatinine test and eGFR explained.

Other tests your doctor may use

• Blood pressure, checked at most diabetes visits, because it affects the kidneys directly.
• HbA1c, a blood test that reflects average blood sugar over about the last two to three months.
• Potassium and other electrolytes, especially when kidney function is reduced or when some medicines are used.
• Urinalysis, which can show blood or infection in the urine.
• A kidney ultrasound, if the doctor wants to look at the size and shape of the kidneys.

How often are these tests done?

KDIGO 2022 and the American Diabetes Association advise a urine ACR and eGFR at least once a year for people with type 2 diabetes from the time of diagnosis, and for people with type 1 diabetes starting about five years after diagnosis. People whose results are already abnormal are usually tested more often. Your doctor will advise on the timing that suits you.

Preparing for the tests

• Ask the lab or clinic whether there is anything you need to do beforehand. Most people do not need to fast for these tests, but if other blood tests are being done at the same time, the instructions may differ.
• For the urine ACR, the lab may ask for the first urine of the morning. Try to avoid very hard exercise the day before.
• If you are unwell with a fever or urine infection, or are menstruating, mention it. The test may be better done another day.
• Bring a list of your medicines and any previous kidney results.

Understanding your results

These tests are useful, but one result does not make a diagnosis. A doctor looks at eGFR and ACR together, repeats them over time, and considers your blood pressure, blood sugar, other tests and history. If you have a result and are not sure what it means, our I have a kidney test result page explains what each test measures. Then take the report to your doctor.

Getting tested in Mombasa

Urine ACR and creatinine tests are available at many laboratories and hospital outpatient clinics in Mombasa, including on Mombasa Island and in Nyali, Bamburi, Likoni and Changamwe. Many people have the tests done at a lab and bring the printed results to their diabetes clinic or physician. For help finding a verified testing provider, see kidney testing in Mombasa.

This page explains what a test or condition involves. It is not a diagnosis and does not replace advice from a doctor who knows your history. Your results should be interpreted together with your symptoms, other tests and a clinical assessment. Medical disclaimer.