Internal Medicine: Open Access
Open Access

Detecting Chronic Kidney Disease: Screening and Diagnostic Tests

Sarah Davis^{* *}Correspondence: Sarah Davis, Department of Hematology, AIIMS University, Delhi, India, Email:

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Description

Chronic Kidney Disease (CKD) is a progressive condition characterized by the gradual loss of kidney function over time. The kidneys are vital organs responsible for filtering waste and excess fluids from the blood, which are then excreted in urine. As kidney function declines, these waste products can accumulate, leading to serious health complications. Detecting CKD early is crucial for effective management and treatment, which can slow disease progression and improve quality of life.

Understanding chronic kidney disease

CKD often progresses silently with few symptoms in its early stages, making early detection challenging. The disease is typically classified into five stages, based on the Glomerular Filtration Rate (GFR), a measure of how well the kidneys are filtering blood. Stage 1 indicates normal or high function, while Stage 5 represents kidney failure, requiring dialysis or transplantation.

Several risk factors increase the likelihood of developing CKD, including diabetes, hypertension, cardiovascular disease, a family history of kidney disease, age over 60, and certain ethnicities. Regular screening is recommended for individuals at high risk to catch the disease in its early stages.

Screening for CKD

Screening for CKD involves tests that can detect early signs of kidney damage even before symptoms appear. The two primary tests used in screening are urine tests and blood tests.

Urine tests

Urinalysis: A simple urine test that checks for abnormalities such as blood, protein, glucose, and signs of infection. Presence of protein in the urine (proteinuria) can be an early indicator of kidney damage.

Albumin-to-Creatinine Ratio (ACR): This test measures the amount of albumin (a type of protein) compared to creatinine (a waste product) in the urine. An elevated ACR indicates albuminuria, suggesting kidney damage. Persistent albuminuria is a hallmark of CKD and is often used to assess the severity of kidney damage.

Blood tests

Serum creatinine: This test measures the level of creatinine in the blood. Since creatinine is a waste product normally removed by the kidneys, elevated levels suggest impaired kidney function.

Estimated Glomerular Filtration Rate (eGFR): Derived from serum creatinine levels, age, sex, and race, eGFR estimates how well the kidneys are filtering waste. It is the most common indicator of kidney function. An eGFR below 60 mL/min/1.73 m² for three months or more indicates CKD.

Regular screening is particularly important for people with diabetes or hypertension, as these conditions are leading causes of CKD. Early detection through these tests can significantly alter the course of the disease through timely intervention and management.

Diagnostic tests for CKD

When CKD is suspected or detected through screening, further diagnostic tests are employed to confirm the diagnosis, determine the underlying cause, and assess the extent of kidney damage. These tests include more detailed blood and urine tests, imaging studies, and sometimes a kidney biopsy

Comprehensive blood tests

Blood Urea Nitrogen (BUN): Measures the amount of nitrogen in the blood that comes from urea, a waste product formed from the breakdown of proteins. High BUN levels can indicate impaired kidney function.

Electrolytes and minerals: Tests for sodium, potassium, calcium, phosphorus, and bicarbonate help assess the kidneys' ability to maintain balance in the body's fluids and electrolytes.

Hemoglobin and hematocrit: Evaluates for anemia, a common complication of CKD due to reduced erythropoietin production by the kidneys.

Advanced urine tests

24-hour urine collection: Measures the total amount of protein and other substances excreted in urine over a 24-hour period. This test provides a comprehensive assessment of kidney function and protein loss.

Microalbuminuria test: Detects smaller amounts of albumin in the urine than the standard ACR test, useful in early stages of CKD, especially in diabetic patients.

Imaging studies

Ultrasound: Provides images of the kidneys, helping to identify structural abnormalities, obstructions, cysts, or tumors. It is noninvasive and commonly used in CKD diagnosis.

CT scan and MRI: Offer detailed images and are used when more precise information is needed, such as detecting kidney stones, tumors, or abnormalities in blood flow to the kidneys.

Doppler ultrasound: Assesses blood flow to and from the kidneys, useful in diagnosing conditions like renal artery stenosis.

Kidney biopsy

Procedure: Involves taking a small sample of kidney tissue using a needle. The tissue is then examined under a microscope to determine the type and extent of kidney disease.

Uses: Particularly useful when the cause of CKD is unclear, or when specific kidney conditions, such as glomerulonephritis or interstitial nephritis, are suspected.

The role of regular monitoring

Once CKD is diagnosed, regular monitoring of kidney function and associated complications is essential. This includes periodic blood and urine tests to track disease progression, manage complications, and adjust treatments as needed. Monitoring also involves blood pressure control, managing blood glucose levels in diabetics, and dietary modifications to reduce the burden on the kidneys.

Patients with CKD should work closely with their healthcare providers to establish a monitoring schedule that suits their condition. This proactive approach helps in delaying progression to kidney failure and improves the overall quality of life.

Conclusion

Early detection and diagnosis of Chronic Kidney Disease (CKD) through screening and diagnostic tests are critical in managing the disease effectively. Regular screening, particularly for highrisk individuals, can identify CKD in its early stages when interventions are most effective. Comprehensive diagnostic tests help confirm the diagnosis, determine the underlying cause, and guide treatment strategies.