Sodium is important for blood pressure maintenance and fluid balance in your body, however most people consume too much of it. Abnormal levels of sodium can put your kidneys under greater strain, which can in turn lead to kidney disease.


Urea is a waste product made by the breakdown of proteins in your body. Healthy kidneys should remove around 90% of the urea from your blood. Higher than usual concentrations of urea suggest your kidneys aren’t functioning as they should be.


Creatinine is a waste product made from the normal breakdown of muscle tissue. Healthy kidneys should remove creatinine from your blood. This means that a raised creatinine level may be caused by impaired kidney function.


eGFR (estimated glomerular filtration rate) is a calculation of the amount of blood filtered through your kidneys over a period of time. It is used as a measurement of how efficiently your kidneys are working. eGFR is a particularly useful way to screen for and detect impaired kidney function at an early stage. A persistently low eGFR is also associated with an increased risk of cardiovascular disease.