What is low kidney function?
Amandeep Khurana, MD, is a nephrologist at Banner Good Samaritan Medical Center in Phoenix.
Question: My doctor said my kidney function is low. What does that mean?
Answer: Normally, we have two kidneys located on each side of our spine, above the waist. Their main job is to filter wastes and excess water out of your blood to make urine. They also maintain the body’s proper chemical balance, help control blood pressure, and produce hormones.
Chances are, you feel normal and were surprised to hear that you have low kidney function (also called CKD or chronic kidney disease). It is called a “silent” disease, because many people don’t have any symptoms until their kidneys are about to fail completely. The only way to know is to get your kidney function checked with blood and urine tests. Your doctor probably checked your kidney function in two ways.
The first is a blood test checks your creatinine level. The kidneys filter waste products and toxins from the body. When the kidney function decreases, those toxins accumulate in the blood. We measure the creatinine to estimate that accumulation. The worse the kidney function, the higher the creatinine level. The level of creatinine in the blood is a useful guide to kidney function, but the glomerular filtration rate (GFR) is a more accurate measure. It is estimated using the blood creatinine along with other variables like age, sex and race. The second of the two tests is a urine test check for albumin. Albumin is a protein that can pass into the urine when the kidneys are damaged.
CKD means that your kidneys are damaged and can’t filter blood like they should. This damage can cause wastes to build up in your body which can lead to other problems that can harm your health. CKD is often a “progressive” disease, which means it can get worse over time, which is why this needs to be taken seriously.
Things to remember:
- Twenty-six million Americans have CKD and millions of others are at increased risk.
- Early detection can help prevent the progression of kidney disease to kidney failure.
- Glomerular filtration rate (GFR) is the best estimate of kidney function.
- High-risk groups include those with diabetes, hypertension and family history of kidney disease.
- African Americans, Hispanics, Pacific Islanders, Native Americans and seniors are at increased risk.
- Two simple tests can detect CKD: urine albumin and serum creatinine.
- Appropriate management can delay or prevent complications and the need for dialysis or transplantation.