Chronic Kidney Disease Tests

Tests for Chronic kidney disease

Doctors use the CGA system to understand how severe CKD is and to decide the best treatment. It looks at three things:

1. C – Cause: What is causing the kidney disease (for example, diabetes or high blood pressure)?
2. G – GFR (Glomerular Filtration Rate): A blood test that shows how well your kidneys are filtering waste from your blood. A normal GFR is usually 90 or higher, although it naturally decreases with age.
3. A – Albuminuria: A urine test that checks whether protein (albumin) is leaking into the urine. Healthy kidneys keep protein in the blood, so protein in the urine is an early sign of kidney damage.

Why are both GFR and albumin important?

Two people can have the same GFR but very different kidney health depending on how much protein is leaking into their urine. For this reason, KDIGO recommends that people at risk of CKD have both tests:

• GFR to measure kidney function.
• ACR (Albumin-to-Creatinine Ratio) to measure how much protein is leaking into the urine.

Together, these tests help doctors detect kidney disease early, determine its stage, and estimate the risk of it getting worse. Your doctor will look at both your GFR and ACR results, along with the cause of your kidney disease, to understand your kidney health and plan the most appropriate treatment.

In many CKD patients, previous renal disease or other underlying diseases are already known. A small number present with CKD of unknown cause.

• Assessment of GFR is the best test to measure the level of kidney function and determine the stage of kidney disease.
• Urinary tract ultrasound and abdominal ultrasound, in which the size of the kidneys is measured. Kidneys with CKD are usually smaller (< 9 cm) than normal kidneys, with notable exceptions such as in diabetic nephropathy and polycystic (multiple cysts) kidney disease. 
• Gradual rise in serum creatinine (over several months or years) and haemogram or complete blood count (used for screening disorders such as anaemia, infection and other diseases). 
• Additional tests may include nuclear medicine MAG3 scan to confirm blood flows and establish the differential function between the two kidneys. 
• DMSA (Dimercaptosuccinicacid) scans are used to measure, for example, the proportionate function of each kidney.
• Kidney biopsy, which is done in some cases to check for a specific type of kidney disease, to see how much kidney damage has occurred and help plan treatment. To do a biopsy, the doctor removes small pieces of kidney tissue and looks at them under a microscope.