Top 5 Kidney Tests Every Diabetic Should Do Annually

What are Kidney Function Tests?

Kidney function tests are essential and include evaluating urine and blood to assess kidney function. Your kidneys support overall health by filtering waste products and balancing fluid and electrolyte levels. Both blood and urine samples are indicators of kidney function and a preventive measure against chronic kidney disease (CKD).

With a better understanding of kidney function tests, let’s explore some of the major tests for a proactive treatment plan and a healthy lifestyle.

5 Types of Kidney Function Test You Must Know

A reliable renal function test is a method for assessing kidney damage in people with diabetes, often before symptoms appear. A study suggests that 44% of type 2 diabetes (T2D) patients suffer from diabetic kidney disease ^[2].

Let’s explore what tests are done to check kidney function and its overall capacity:

1. Serum Creatinine Test

The serum creatinine test is the most common test used to assess kidney function and filtration capacity. People suffering from diabetes, high creatinine levels may lead to kidney failure.

• Normal reference range: Around 0.6–1.2 mg/dL in adults, varying by age, sex, and muscle mass.
• Mild elevation: Levels slightly above normal may suggest early reduction in kidney filtration and require monitoring.
• High creatinine levels: Persistent readings above 1.5 mg/dL often indicate significant kidney impairment or chronic kidney disease.

The score or results of the serum creatinine test are used in combination with eGFR for accurate analysis and diagnosis.

2. Estimated Glomerular Filtration Rate (eGFR)

While creatinine is significant, eGFR is the “gold standard” for determining exactly how well our kidneys are functioning. It is a calculation based on your serum creatinine, age, and gender.

Think of eGFR as a percentage of kidney function.

• 90 or higher: Normal kidney function.
• 60 to 89: Mild loss of function (needs monitoring).
• Below 60: Indicates chronic kidney disease (CKD). This is a core component of any renal function test and helps your doctor accurately stage kidney disease.

3. Blood Urea Nitrogen (BUN)

Blood Urea Nitrogen (BUN) is a supportive kidney function test that measures the amount of urea nitrogen in the blood. In diabetics, abnormal BUN levels may indicate reduced kidney efficiency or dehydration-related stress.

• Normal reference range: Typically 7–20 mg/dL in adults, depending on laboratory standards.
• Mild elevation: A slightly elevated BUN may occur due to dehydration, high protein intake, or early kidney strain.
• High BUN levels: Persistent values above 20–25 mg/dL can suggest impaired kidney function or reduced blood flow to the kidneys.

The test is a cofactor for the serum creatinine test and is effective in detecting kidney-related metabolic diseases.

4. Urine Albumin-to-Creatinine Ratio (uACR)

The urine albumin-to-creatinine ratio (uACR) is a key kidney function test that detects early kidney damage, especially in people with diabetes. It identifies protein leakage in urine before blood tests show abnormalities.

• Typical range: Below 30 mg/g, indicating healthy kidney filtration with no significant protein loss.
• Moderately increased albuminuria: 30–300 mg/g, suggesting early diabetic kidney damage that needs close monitoring and control.
• Severely increased albuminuria: Above 300 mg/g, often linked to advanced kidney disease and higher cardiovascular risk.

uACR provides comprehensive information on early intervention and accurate diagnosis alongside eFGR for disease detection.

5. Serum Electrolytes (Sodium and Potassium)

Serum electrolyte tests are an essential part of a kidney function test, as the kidneys regulate sodium and potassium balance. In diabetes, kidney impairment can disrupt electrolyte balance, leading to serious complications.

• Normal sodium range: 135–145 mEq/L, essential for fluid balance and nerve function.
• Normal potassium range: 3.5–5.0 mEq/L, critical for heart rhythm and muscle activity.
• Abnormal levels: Low or high sodium and potassium may indicate impaired kidney regulation or medication effects.

The results are monitored to prevent cardiac and neuromuscular diseases.

A specialist should always review abnormal electrolyte results, and consulting the best nephrologist in Kolkata helps ensure timely correction and long-term kidney protection.

Primary Causes That Affect the Renal Health of Diabetic Patients

Diabetes places continuous stress on the kidneys, gradually impairing their filtering ability over time. Studies indicate that 34.4% of people with diabetes develop some degree of diabetic kidney disease ^[3].

• Poor blood sugar control: Persistently high glucose damages kidney blood vessels, reducing filtration efficiency and accelerating kidney function decline.
• Uncontrolled high blood pressure: Hypertension increases pressure within the kidney filters, worsening structural damage in diabetic patients.
• Long duration of diabetes: The risk of kidney damage rises significantly after 10–15 years of diabetes without strict metabolic control.
• Proteinuria: Albumin loss reflects early kidney injury and often precedes a measurable decline in filtration rate.
• Use of nephrotoxic medications: Frequent use of painkillers or unmonitored drugs can further strain already vulnerable diabetic kidneys.

Also read: Kidney Problems in Winter: Key Risks and Solutions

Signs and Symptoms to Get a Kidney Function Test

Kidney damage often develops silently in people with diabetes, making early testing essential. Recognising warning signs helps prompt timely evaluation and prevents further kidney deterioration.

• Swelling in feet or ankles: Fluid retention may indicate reduced kidney filtration and impaired waste removal.
• Changes in urination pattern: Frequent urination, foamy urine, or reduced output can signal kidney dysfunction.
• Unexplained fatigue or weakness: Toxin buildup due to poor kidney function often causes persistent tiredness.
• Poor blood sugar or blood pressure control: Difficulty managing glucose or pressure may reflect underlying kidney involvement.