Why You Should Get a Kidney Function Test Regularly?

Kidneys are a part of the excretory system of the body and help in maintaining the electrolyte balance, blood pressure, and filtering wastes from the blood. Kidney dysfunction often goes unnoticed despite its crucial role in sustenance. Regular testing of kidney functions is essential for early detection and prevention of kidney diseases. Let us understand the tests used to assess kidney function, their benefits, and how regularly they need to be done to monitor our kidney functions. 

What is the role of the kidney?

The kidneys play a major role in filtering wastes and excess fluid from the blood, maintaining electrolyte balance, keeping bones healthy, maintaining blood pressure, and synthesizing red blood cells. 

Where do kidney function tests play a role? 

• Early detection of kidney diseases is essential because these conditions often progress without any evident signs or symptoms. Regular and frequent testing can prevent progressive damage by ensuring timely intervention. 

• Chronic conditions such as diabetes, and hypertension over long periods can affect the kidneys. Keeping an eye on kidney functions helps prevent complications and allows for modification of current treatment regimens.

• Certain medications when taken for long-term disorders can put stress on the kidney and cause damage as an adverse effect. These medicines include Non-steroidal Anti-inflammatory drugs (NSAIDs), certain chemotherapeutic drugs, and antibiotics. People on such medications should regularly perform kidney function tests to prevent such damage. If the tests show evidence of alteration in kidney function, the dosage of these implicated drugs can be tapered, or treatment can be changed, based on the clinician's discretion. 

• Role of kidney function tests in treatment guidance: In patients with diagnosed kidney dysfunction, regular kidney function tests help track the improvement with medication and play a role in deciding the need for a change in treatment. 

• Complications of kidney dysfunction can range from electrolyte imbalances to cardiovascular accidents. Kidney function tests help prevent the occurrence of such consequences. 

Who should undergo regular kidney function tests? 

Kidney function tests are beneficial for everyone. However, people who are at a higher risk include diabetics, hypertensives, people with a family history of kidney diseases, those who are on medications that can cause renal damage, and elderly people. 

What are the various kidney function tests?

1. Blood tests for kidney function:

• Serum creatinine: Creatinine is a metabolic waste product produced by the breakdown of muscles and proteins. Creatinine is filtered out from the blood by the kidneys. Measuring the level of creatinine in the blood estimates kidney function. 

• Blood Ure Nitrogen (BUN): Urea is a byproduct of protein metabolism and is filtered out by the kidneys. BUN levels tell you the amount of urea and nitrogen in the blood. High levels can indicate kidney dysfunction. 

• Estimated glomerular filtration rate (eGFR): eGFR can assess kidney function and determine the stage of the kidney disease. It is calculated based on the serum creatinine levels, age, gender, and body size. Low eGFR levels indicate reduced kidney function. ​

  2. Urine tests

• Urine analysis: Analysis of the urine determines the presence of various compounds in the urine such as glucose, protein, blood, and others. The presence of protein in the urine is among the first signs of kidney dysfunction. 

• Albumin: creatinine ratio (ACR): This gives an idea of the amount of albumin in the urine and is a more accurate measure of proteinuria. A higher level than normally indicates kidney dysfunction. 

3. Role of radiology in kidney function assessment:

• Imaging the kidneys by an ultrasound or a CT scan offers information on the size of the kidneys, the presence of any obstruction, tumor, or stones, or any other abnormalities. 

4. Kidney biopsy:

Kidney biopsy is a procedure done to remove a small piece of the kidney to determine the diagnosis, the extent of damage, or to see the response to treatment. The tissue is examined under the microscope and special tests are done to reveal very valuable information. 

How regular should your kidney function tests be?

• For people who are not at risk, have no co-morbidities, or are on medications that can cause kidney dysfunction, a kidney function test every one to three years might suffice. 

• For people with risk factors, such as elderly people, those with chronic diseases including hypertension and diabetes, and those with a family history of kidney diseases, every 6 months to a year would be the recommended frequency for kidney function testing. 

• However, it is best to consult your treating physician for the ideal testing schedule based on your medical condition. 

Understanding kidney function test results:

Know what your results mean. Here is a brief explanation of your kidney test results:

• Serum creatinine: In healthy adult men, creatinine levels should range between 0.74-1.35mg/dl. For healthy adult women, a range of 0.59-1.04 mg/dl is acceptable. Increased levels can mean kidney dysfunction. 

• BUN: Normal BUN levels are 5-20 mg/dl. Higher levels may indicate kidney disorder or dehydration. 

• eGFR: eGFR levels above 90ml/min/1.73m2 are considered normal. Chronic kidney diseases are usually characterized by levels below 60ml/min/1.73m2 for over three months. 

• Albumin: creatinine ratio: This ratio is expected to be below 30mg/g in normal individuals. Higher levels may point to kidney damage. 

Maintaining kidney health in early kidney diseases:

Lifestyle modifications and regular medication can significantly retard the progression of kidney diseases in the early stages. Here are some steps that can help:

• Maintaining blood pressure: Increased blood pressure levels can constrict blood vessels and reduce blood flow to the kidneys, causing damage. Keeping blood pressure in check can prevent this injury.

• Reducing blood sugar levels in diabetics: Diabetes also causes damage to the blood vessels, leading to kidney damage. Controlling blood sugar levels can help maintain kidney health.

• Diet modifications to protect your kidney: To control your blood sugar levels and hypertension, consume foods with less salt and sugar. Avoid eating foods rich in potassium and phosphorous as these minerals in excess can damage kidneys. Too much protein in your diet can also strain your kidneys, so meat and foods such as legumes must be taken in moderation. 

• Maintain your hydration levels: Adequate water consumption is a must to keep your kidneys functioning properly. 

• Avoid medications with possible side effects on the kidneys: Certain herbs, ayurvedic preparations, supplements, and over-the-counter medicines can damage kidneys. So, consult your physician before consuming any of these.