‘Can kidney damage be detected through a blood test or is imaging (ultrasound, CT scan) necessary?’

Early detection through these simple tests can go a long way in preventing chronic kidney disease and the need for dialysis later on

Here's what you should consider (Photo: Getty Images/Thinkstock)

3 min readNew DelhiNov 18, 2025 06:00 AM IST First published on: Nov 18, 2025 at 06:00 AM IST

Kidney health can be effectively assessed through simple blood and urine tests. In most cases, this is the first and most important step. So, are imaging like ultrasound or CT scans necessary? That’s exactly what a Quora user wanted to know: “Can kidney damage be detected through a blood test or is imaging (ultrasound, CT scan) necessary?” To understand in detail, we reached out to experts.

“The serum creatinine test and the estimated glomerular filtration rate (eGFR) are key indicators of how well your kidneys filter waste from the blood. Additionally, urine tests help detect protein or blood, which are often early signs of kidney disease,” said Dr Nikhil Bhasin, consultant nephrologist and renal transplant physician, Wockhardt Hospitals, Mumbai Central.

Dr Mahesh Prasad, senior consultant nephrology, KIMS Hospitals, Thane, added that there are many other better and earlier markers like KIM1, NGAL, B2 microglobulin, etc, but not readily available as of now.

But blood and urine tests alone don’t give the full picture, noted Dr Mahesh. “They indicate that kidney function is impaired, but not necessarily why. That’s where imaging techniques like ultrasound or CT scans become useful. It helps identify structural causes such as kidney stones, blockages, scarring, or congenital abnormalities,” said Dr Mahesh.

In simple words, these tests typically examine the structure of the kidneys, check for obstructions like stones, cysts, or tumours, and assess kidney size or shape.

However, imaging, such as ultrasound or CT scans, is not always the first step in evaluation, contended Dr Bhasin, adding that it’s important to note that imaging can “look normal even when kidney function is reduced, because these scans show the anatomy, not how the kidneys perform”.

So, both tests have distinct roles. “Blood and urine tests assess how well the kidneys are working, while imaging helps uncover why they might not be functioning properly. For screening or early detection, always start with blood and urine tests. If those show abnormalities, imaging can be used to investigate the structural cause further,” said Dr Bhasin.

Here’s what the user asked (Photo: Quora)

Think of it this way. Blood tests reveal performance, while imaging reveals structure, explained Dr Mahesh. “For someone at risk like diabetics, hypertensives, or those with a family history, regular blood and urine monitoring is crucial. Imaging is advised only when there’s an abnormality or specific symptom like flank pain, swelling, or blood in urine,” said Dr Mahesh.

Also Read | Which damages the kidney more – high blood pressure or sugar?

Early detection through these simple tests can go a long way in preventing chronic kidney disease and the need for dialysis later on.

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.