Chronic kidney disease (CKD) doesn’t usually announce itself. Unlike injuries or infections, kidney damage can develop slowly and quietly, often going unnoticed until it becomes serious. For many people, the earliest clues show up not in how they feel, but in routine lab results.
“There is no glaring, scary symptom that occurs when the kidneys start to become damaged,” said Matthew Van Norman, DO, a nephrologist at UT Physicians Renal Disease and Hypertension – Texas Medical Center and assistant professor at McGovern Medical School at UTHealth Houston. “Unfortunately, when symptoms do begin to become noticeable, the kidney function has already dropped to kidney failure territory.”
Symptoms of kidney dysfunction
Most people are born with two kidneys, located below the rib cage on each side of their spine. The kidneys’ main job is to filter waste from the blood to produce urine while keeping essential substances the body needs. When the kidneys start to lose function, toxins and waste can build up in the body, affecting multiple systems. Most people don’t notice these changes, but kidney dysfunction still increases the risk for cardiovascular disease and other health problems.
When symptoms do appear, they are often vague and can be linked to many conditions. Symptoms may include:
- Fatigue
- Trouble sleeping
- Loss of appetite
- Itching
- Weakness
- Change in taste
- Dry skin
What lab results can reveal
The good news is that kidney disease can often be detected early through routine blood and urine tests your primary care provider may already order.
A standard metabolic panel includes a creatinine test, which helps estimate how well the kidneys are functioning. That number is used in a calculation called the estimated glomerular filtration rate or eGFR.
Van Norman said it can be helpful to think of eGFR as a percentage of kidney function on a scale from 0 to 100. A reading above 90 is considered normal. Levels between 30 and 59 indicate stage 3 CKD and typically prompt a referral to a kidney specialist. A value under 15 indicates end-stage renal disease.
“We don’t have a noninvasive way of checking exactly how the kidney is functioning, but we do have these lab markers, such as creatinine, to help us estimate,” Van Norman said.
Urine tests are another important tool. When kidneys are damaged, protein can leak into the urine, which means an increased risk of kidney disease progression and heart disease.
The power of early detection
People at higher risk for developing CKD include those with diabetes, high blood pressure, heart disease, obesity, or a family history of kidney disease.
If caught early, the progression of CKD can often be slowed. Treating the underlying cause — most commonly diabetes or high blood pressure — is a critical first step. Other contributors may include genetic conditions or autoimmune disorders.
“The earlier we detect kidney disease, the earlier we can work to slow its progression, reduce the risk of complications, and improve quality of life,” Van Norman said. “I’ve had many patients show improved or stable kidney function after making lifestyle changes.”
Adapting lifestyle factors
Diet, physical activity, and sleep habits have a major impact on kidney health, Van Norman said. He admits it’s a simple answer that isn’t always easy to maintain.
His recommendations include:
- Eating more fresh produce or frozen vegetables, lean meats, and whole grains
- Limiting fried and highly processed food
- Move with purpose for about 45 minutes a day, which can be as simple as walking
- Sleeping six to eight hours per night
“When it comes to your kidneys, just because nothing feels wrong doesn’t mean everything is fine,” Van Norman said. “Just like we schedule routine checkups and maintenance for our cars, we need to do the same for ourselves.”