The kidneys are doing more than most people give them credit for. Positioned on either side of the spine just below the rib cage, these two fist-sized organs filter roughly half a cup of blood every minute, removing waste, excess fluid, salt, and minerals and sending them out of the body as urine. They also regulate blood pressure, balance electrolytes, support red blood cell production, and help keep bones strong. When they stop doing those jobs well, the consequences touch nearly every system in the body.
Chronic kidney disease develops when the kidneys sustain damage over a period of months or years. That damage can stem from a number of underlying conditions, and it does not always get better once the original cause is identified and treated. The kidneys can continue to decline even after the triggering condition is under control.
Why chronic kidney disease is so easy to miss
The most disorienting thing about chronic kidney disease is that it often produces no symptoms at all in its early stages. Most people do not know they have it until the condition has already progressed significantly. By the time symptoms appear, such as nausea, vomiting, loss of appetite, fatigue, sleep disruption, difficulty concentrating, shortness of breath, or blood pressure that no longer responds to medication, the kidneys are typically operating at a fraction of their normal capacity.
That silent progression is what makes routine screening so important, particularly for people who carry known risk factors. High blood pressure and diabetes are the two leading causes of chronic kidney disease in the United States. Autoimmune conditions, including lupus, also raise the risk considerably.
How chronic kidney disease is diagnosed
Because symptoms are often absent in the early stages, diagnosis typically happens through testing rather than through reported complaints. Blood tests measure the estimated glomerular filtration rate, or eGFR, which tells clinicians how much blood the kidneys are filtering per minute. Urine tests look for protein or trace amounts of blood, both of which can indicate kidney stress or damage. Imaging tests such as ultrasound or CT scans may also be used to examine the kidneys directly.
The five stages of chronic kidney disease
Kidney disease is staged according to eGFR results, with each stage reflecting a different degree of kidney function. Stage 1 is characterized by an eGFR of 90 or above, indicating healthy kidney function. Stage 2 covers an eGFR of 60 to 89 and reflects mild loss of function. Stage 3a runs from 45 to 59 and represents mild to moderate loss. Stage 3b covers 30 to 44 and indicates moderate to severe loss. Stage 4 spans 15 to 29 and signals severe loss of function. Stage 5, with an eGFR below 15, is classified as kidney failure and is also referred to as end-stage kidney disease.
End-stage kidney disease is fatal without intervention. The two treatment options at that point are dialysis, which mechanically performs the filtration work the kidneys can no longer do, or a kidney transplant. Neither is a cure, but both can sustain life.
Chronic kidney disease and when to see a specialist
People who have diabetes, high blood pressure, lupus, or other conditions associated with kidney risk should be monitored on a regular schedule. That typically means blood and urine tests every six to twelve months to track eGFR and check for protein in the urine. If those results indicate a problem, the next step is a referral to a nephrologist, a physician who specializes in kidney disease and can guide more targeted treatment.
Treatment for chronic kidney disease focuses on slowing its progression. That usually means managing whatever underlying condition is driving the damage, whether that is keeping blood pressure within a healthy range, controlling blood sugar levels, or addressing inflammation from an autoimmune condition. There is no treatment that reverses kidney damage already done, which is why early detection, achieved through routine testing before symptoms appear, carries so much weight in long-term outcomes.
