Evaluating Kidney Health Through Function Tests healthcare nt sickcare

How to Test for Kidney Function?

Kidney function tests are crucial for assessing how well the kidneys are filtering waste and maintaining body homeostasis. A key test is checking creatinine levels, which indicate kidney function status. Read on to understand these important laboratory tests.

What all Checked in Kidney Function Tests?

Kidney function tests, also called renal function tests, analyse different substances and factors to determine how efficiently the kidneys are working.

Some key markers checked include:

  • Creatinine: A waste product from muscle activity, its level indicates kidney filtration ability. High creatinine denotes impaired function.
  • Blood Urea Nitrogen (BUN): The urea nitrogen filtering capacity of kidneys is measured. High BUN indicates kidney disease.
  • Electrolytes: Levels of sodium, potassium, and chloride. Electrolyte imbalance points to improper kidney function.
  • Glomerular Filtration Rate (GFR): GFR is the best way to check overall kidney function. Low GFR signals kidney damage.
  • Albumin: Excess albumin in urine indicates early kidney damage.
  • pH: Abnormal urine pH points to metabolic or kidney disorders.

Why is the Creatinine Test Important?

Creatinine is a key indicator of kidney function. A simple blood creatinine test can reveal important information:

  • Glomerular filtration rate (GFR): Creatinine levels help estimate GFR, which measures how much blood the kidneys filter per minute. GFR denotes kidney function status.
  • Early kidney disease: Increased creatinine is often the first sign of impaired kidney function, as it is an early marker of dysfunction. Catching it early allows treatment to prevent further damage.
  • Monitor kidney disease: Creatinine levels help track the progression of chronic kidney disease and how well treatment is working.
  • Check kidney transplant health: Creatinine is measured to evaluate how well a transplanted kidney is functioning.
  • Muscle health: Higher creatinine may indicate reduced muscle mass due to conditions like muscular dystrophy.

What Abnormal Creatinine Levels Indicate?

  • High creatinine: Levels above 1.2 mg/dL indicate impaired kidney function and need further evaluation.
  • Low creatinine: Levels below 0.6 mg/dL can reflect lower muscle mass, malnutrition, and liver disease.
  • Fluctuating levels: Changing creatinine may signal an improvement or worsening of kidney function. Trends offer useful insights.
Why are kidney function tests done?

To check kidney health, screen for kidney disease, monitor existing disease and adjust treatment plans.

What is checked in a kidney function blood test?

Creatinine, BUN, electrolytes like sodium and potassium, glomerular filtration rate (GFR) and more.

When should kidney function be tested?

Annually for adults, or if you have diabetes, hypertension, family history of kidney disease.

How often should kidney function be monitored if diseased?

Your doctor determines frequency (e.g. every 3–6 months) based on severity to adjust medications promptly.

Tips to Keep Kidneys Healthy

  • Drink plenty of fluids, especially water
  • Control blood sugar and blood pressure
  • Eat less salt and protein
  • Maintain a healthy weight
  • Exercise regularly
  • Avoid overusing painkillers
  • Don't smoke

Kidney function tests provide vital markers of kidney health and early signs of disease. Make sure to get tested regularly, follow up on abnormalities, and take steps to preserve kidney function. Healthy kidneys equal a healthy you!

When to See a Doctor About Kidney Function?

See your doctor promptly if you have any of the following:

  • Persistent signs like nausea, vomiting, fatigue, appetite loss
  • Swelling in the legs, ankles, or feet
  • Difficulty urinating or decreased output
  • Pain in the back or side below the ribs
  • High blood pressure that is difficult to control
  • Blood or protein in the urine
  • Foamy or dark-coloured urine

Get tested right away if you have risks like diabetes, hypertension, heart disease or a family history of kidney disease. Early detection and treatment can slow or prevent further damage.

Doctors may recommend specialists like a nephrologist (kidney doctor) with expertise in managing kidney disorders and an individualized treatment plan.

Can Kidney Function Be Improved?

If detected early, treating underlying causes like diabetes can help improve kidney function significantly in many cases. Controlling blood pressure is also key.

Lifestyle changes like weight management, low sodium diet, exercise, adequate hydration and smoking cessation also benefit kidney health.

Medications called ACE inhibitors and ARBs help expand blood vessels and lower blood pressure, reducing further kidney damage.

If the function is very poor, doctors discuss options like temporary dialysis or even kidney transplant evaluation for permanent damage.

While the kidneys have some ability to heal and regain function with proper treatment, significant or long-term damage cannot be reversed. Hence, early detection is key.

The Importance of Monitoring Kidney Function

  • Detects early signs of kidney disease for timely treatment
  • Helps adjust blood pressure and diabetes medications
  • Guides treatment decisions for kidney disorders
  • Monitors kidney health if taking potentially toxic drugs
  • Tracks the function of a transplanted kidney
  • Assesses suitability for contrast dye procedures
  • Indicates the presence of systemic conditions like lupus

Work with your doctor and follow their recommended schedule for kidney function testing. Listen to your body and watch for any symptoms. Caring for your kidneys is a vital part of staying healthy.

How is GFR calculated, and what do the stages mean?

Glomerular filtration rate (GFR) is considered the best indicator of kidney function. It measures how much blood the kidneys filter per minute.

GFR is calculated using the creatinine level in blood, along with factors like age, gender and body size.

Based on GFR levels, chronic kidney disease is classified into 5 stages:

  • Stage 1: GFR 90+: Normal kidney function
  • Stage 2: GFR 60-89: Mild loss of function
  • Stage 3: GFR 30-59: Moderate loss, kidney damage
  • Stage 4: GFR 15-29: Severe loss of function
  • Stage 5: GFR <15: Kidney failure

Lower GFR indicates worsening kidney function. Declining GFR is a sign of progressive kidney disease if persistently abnormal.

How to Test for Kidney Function?

Kidney function is primarily assessed using blood tests and urine tests:

Blood tests involve drawing a blood sample and analysing levels of creatinine, BUN, electrolytes, and GFR.

Urine tests check urine albumin, protein, pH, specific gravity, and microscopic examination of sediment.

These samples are collected over 24 hours or as a random spot urine sample.

Other imaging tests like ultrasound, CT and MRI scans may also be done to visualize kidney structure in case of suspected abnormalities.

Monitoring kidney function through proper testing helps detect issues early for prompt management. Take care of your kidneys for optimal health!

What Foods Help Boost Kidney Health?

The right diet and nutrition can help support overall kidney function. Some beneficial foods include:

  • Blueberries: Antioxidants reduce inflammation and lower oxalate.
  • Fish: Omega-3 fatty acids fight inflammation and reduce risks.
  • Onions/garlic: Sulphur compounds support kidney detoxification.
  • Olive oil: Monounsaturated fats improve filtering ability.
  • Cranberries: Prevent urinary tract infections that can damage kidneys.
  • Green leafy vegetables: Vitamins C and K, folate help regulate function.
  • Beans & legumes: Vegetable proteins lower hyperfiltration injury.
  • Pumpkin seeds: Anti-inflammatory properties, increase GFR.
  • Apples: Quercetin reduces oxidative kidney damage.
  • Turmeric: Curcumin is a powerful anti-inflammatory for kidneys.
  • Ginger: Gingerol protects kidneys and reduces urea levels.
  • Tart cherry juice: Decreases uric acid accumulation in kidneys.
  • Egg whites: Quality protein without excess phosphorus load.
  • Water: Hydration is vital for flushing toxins from the kidneys.

Making smart dietary choices can truly help improve kidney outcomes and slow disease progression. Consult a nephrologist or dietitian to plan the right kidney-friendly meals.


Kidney function tests provide vital information about the health of the kidneys and their ability to filter wastes from the body efficiently. Have your GFR, creatinine, BUN and other markers tested regularly if at risk or experiencing any symptoms. Treating issues early is crucial to prevent permanent damage. Additionally, healthy foods, hydration, and lifestyle factors can help maintain optimal kidney function. With some diligence, your kidneys can serve you well for life!


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