A reader asks: I was diagnosed with diabetes a couple of years ago, and understand I need to have an annual blood test to check my sugar levels. Recently I’ve been asked to provide a urine sample, but I don’t understand what this is for. I thought checking urine for sugar wasn’t done any more?

Dr Rosemary Leonard replies: Though an initial diagnosis of diabetes may be suspected after finding sugar in urine (using a test strip) you are correct that testing urine for sugar is not done once the diagnosis has been made. 

Though excess sugar in the blood may leak out in urine, a far better way of checking if blood sugar levels are too high is with the glycosylated haemoglobin (HbA1c) level, which gives an indication of blood sugar levels in the previous three months. It’s usually checked via a blood test at least once a year in all diabetics.

Unfortunately, the high blood sugar levels that can occur in diabetes can damage the kidneys. So a blood test for kidney function should also be done at least annually as well, along with a urine test to see if it contains abnormally high amounts of protein, a test known as the albumin: creatinine ratio, or ACR. This can be a good detector of early kidney disease, which is otherwise not causing any symptoms, and will be the test you have been asked to do.

It is easier to tackle kidney disease if it is diagnosed in the early stages. In those with diabetes, this involves making sure blood glucose levels and the blood pressure are really well controlled as both of these can contribute to kidney damage.

Some drugs, such as ACE inhibitors like ramipril or lisinopril, and angiotensin receptor blockers (ARBs) such as losartan or candesartan can help protect kidneys from further damage, as well as lower blood pressure. So one of these is usually prescribed in addition to drugs that help control blood sugar levels.

It is also important to avoid taking medicines that may damage kidneys, especially anti-inflammatories, such as ibuprofen.

If you have a health question for Dr Leonard, email her in confidence at yourhealth@express.co.uk. She regrets she cannot enter into personal correspondence or reply to everyone