Kidney function test – Purpose, types and procedure

Core function of your kidneys is to filter blood. They have the needful physical structure to eliminate waste materials, maintain an optimal level of electrolytes as well as fluid levels. Waste materials – filtered by the kidneys – are discharged out of the body through urine. Kidney does the task of filtering through a large number of filtering agents known as nephrons. Owing to these large numbers, you may not develop any serious signs even if your kidneys are functioning at only say, 15% of standard capacity. When kidneys stop functioning, it can lead to a lot of serious consequences and it can be a fatal condition. Hence, testing the functioning capability of your kidneys becomes a top priority to maintain good renal health.

Every human body has two kidneys; each is located by the side of the spine – i.e., beneath the ribcage and behind the abdomen. Of the many functions your kidneys do, the main activity is to filter your blood and help discharge waste. Kidneys also help your body to make red blood cells, essential vitamins (especially, D) as well as help your body to regulate enzymes / hormones for maintaining an optimal level of blood pressure. Last but not least, kidneys help maintain the correct balance of minerals and fluids.

Medical conditions affecting your kidneys

Nephrology is a science under which kidney function is studied, while urology addresses the disorders pertaining to the anatomy of kidney including your urinary tract. Nephrology deals with pyelonephritis, nephritic syndrome, nephrosis, chronic renal disorders as well as renal injuries. On the other hand, urology focuses on stone formation in kidneys, stones formed in your ureter, blocks in the tract, renal cancers, cysts, etc.Pyelonephritis is a condition wherein kidney suffers an inflammation. This is due to infections of bacteria. It is characterised by a burning sensation while passing urine, urinating more often as well as fever or nausea. This condition is detected with tests such as radiological scans and / or urinalysis.Nephritic syndrome occurs in the glomerulus; this can cause pores to get larger and allow red cells as well as proteins to get into your urine. As a result, protein levels may drop in your blood. Nephrosis is characterised by spotting excessive amounts of proteins in your urine (proteinuria), swelling as well as high levels of lipids.

Chronic renal disease is marked by a slow but steady loss of filtering efficiency. This condition is known to occur over a span of several years. As kidneys are highly resilient, the initial phases of this disease do not present with any distinctive symptoms. However, as the kidneys start losing their efficiency levels, you may notice tiredness, nausea, swelling of legs, etc. This condition may also lead to hypertension, cardiac aliments as well as blood conditions such as anemia.

Oncological conditions

Stone formation in kidneys is marked by a blocked urinary tract or an acute discomfort as well as pain in your abdomen and lower back. These signs are sensed because of formation of stones – of larger than 0.18 inch – in your kidneys; stones of smaller size may get discharged along with urine. But, larger sized stones can lead to vomiting, experiencing pain while urinating and spotting of blood traces in urine.

Stones in ureter occur when those in your kidneys move and block your ureter. These stones often interrupt in the flow of urine. Such blockages eventually lead to acute pain while urine is discharged as well as cramping of the abdomen – especially your lower side. This condition eventually may result in inflammation of your kidneys.

Blocks in your tract can be a congenital condition, an enlarged prostate or can also be due to stones in your bladder. An enlarged prostate is not a malignant development and may make you to urinate more often as well as make you lose control over the bladder.
Cysts are essentially accumulation of fluids in your kidneys. Though most cysts are non-malignant, some may turn into cancerous ones. Such cysts can be surgically operated upon and removed by a procedure known as nephrectomy.

Kidney function tests

The rate at which your kidneys filter is a unit of renal efficiency. This is directly related to the efficiency of your nephrons – which is a basic filtering agent present in the kidneys. Nephrons have wall linings made of cells with absorbing capabilities. These cells facilitate reabsorption of minerals and water. When your kidneys are functioning well, it means they are able to both receive as well as filter blood. Each filtering unit is comprised of two parts – a tuft-shaped glomerulus (a collection of capillaries) and a capsule called as Bowman’s sac. This sac also serves as housing for glomerulus. The unit to measure functioning of kidneys is called rate of glomerular filtration.

Kidney function tests are performed if your doctor suspects a possible renal dysfunction. These tests are also administered if your family history includes conditions such as hypertension, diabetes, etc. Doctors may recommend renal function tests when they observe a few distinctive signs. Such signs include swollen hands or legs, difficulties while urinating (especially with starting to urinate), need to urinate more often, detection of traces of blood in urine, hypertension, etc. Your limbs may get swollen because of an excessive accumulation of water in your body. You may also experience pains while you try to urinate.

If any one of these above signs is experienced, it is not construed as a likely renal problem. But, if more than one of these signs is reported, it is time to opt for kidney function tests. These tests help your doctor to find the rate of glomerular filtration. As mentioned, this filtration rate gives your doctor essential data on how fast (or, swiftly) your kidneys are working.

Types of kidney function tests

One need to be aware of the earliest indicators of a likely problem in your kidneys. For instance, inability to eliminate urea may lead to itchiness. Also, if you notice fluid build-up in your limbs, it may be an early warning of a likely chronic renal condition. However, if fluid accumulation stands ignored, your kidneys may “seek” help by increasing your blood pressure level or may trigger conditions such as anemia, osteoporosis, etc.

Your medical history

Kidney function tests aim to understand how well your kidneys are working. A significant reduction in the functioning capability of kidneys can be due to different kinds of disorders. Your doctor will understand your family’s medical history as well perform a few tests – especially, urinalysis and a scan. While noting down your family’s medical history as well as your own clinical history, your doctor may be extra watchful of conditions such as diabetes, polyuria (passing of unusually large quantities of urine), prior renal disorders, accumulation of fluids (edema), etc.

A thorough physical examination

Your doctor will perform a thorough physical examination of your body. While examining your body, extra attention is paid to look for conditions such as endocarditis, lupus erythematosus, high blood pressure or vasculitis. Endocarditis is a condition wherein an inflammation occurs on the inner layers of your heart. This condition is generally linked to your heart’s valves. It is characterized by several signs; salient ones are loss of bodyweight, weariness, excessive sweating and chills with fever.

Lupus erythematosus is an autoimmune condition wherein your tissues are under attack by your own immune system. Its impact may be felt in many parts of your body including skin, joints, kidneys, etc. This is often accompanied by pain in joints, pain in your chest while breathing, swelling of your lymph nodes, etc. You may also turn extremely sensitive to sunlight.

Vasculitis is an inflammation of vessels transporting blood. It shows up as discoloration of skin or development of dark colored spots on your skin. Such discoloration may be due to reduced flow of blood to the skin-based capillaries. Absence of needful oxygen often shows up as blue colored spots.

Urine tests

Urinalysis is a common test to clinically understand the functioning of your kidneys. It can be done either with a dipstick approach or by studying samples under a clinical microscope. The dipstick approach has a specially treated segment; it is this coated / treated segment which is dipped into a sample of urine. If the sample contains an excessive quantum of sugars, bacteria, proteins, pus or blood, you will notice a change of color. Urinalysis is capable of detecting a wide range of anomalies including stone formation in kidneys, infections in your bladder as well as chronic conditions such as renal diseases.

The filtering capability of the kidneys can be inferred by measuring protein levels in your urine. Your doctor may lay more emphasis to know the incidence of a condition called albuminuria. This condition occurs when your kidneys’ filtering capability is impaired. People without a renal condition may only have minor traces of albumin in their urine. The key sign is the change in the appearance of your urine; it takes a foamy texture. You may also observe swelling of face, hands, stomach or ankles; however, such signs are observed only when the loss of albumin through urine is fairly significant.
This condition may arise when your kidneys are letting large molecules to get into urine. This is not a normal occurrence. Kidneys never let go of larger protein molecules – such as albumin – to remain unfiltered, leave alone making them get discharged through urine. Such drop in filtering capability is more pronounced among people living with Type 1 diabetes.

The quantum of proteins discharged along with urine is measured over a 24-hour time window. If the condition is nephrotic (inflammation of kidneys) in nature, it may lead to discharge of upto 3.5 grams of albumin in a 24-hour period. On the other hand, if it is nephritic, the level of albumin found in urine is far less. Discharge of less than 300 milligrams in 24 hours is termed as microalbuminuria; this condition is considered to result in nephropathy.

Your dietician may recommend you to reduce the intake of red meat. You may also need to monitor your blood pressure levels. Your treating doctor may prescribe drugs blocking angiotensin as a treatment option to reduce hypertension.

Caveat – There can be an increase in protein content in urine if you work out intensely. In some instances, presence of infections can also lead to build-up of proteins in urine.
The urine test may also help assess how soon creatinine – a waste material – is removed from your system. Creatinine is a by-product while proteins are broken down. The quantum of discharge of creatinine is an indicator of the filtering capability of kidneys. A pronounced share of creatinine may also be due to intake of protein-rich foods or dietary supplements to enhance performances. Hence, an increase in creatinine cannot always be a direct metric to assess the filtration rate of kidneys.

Blood tests

A sample of blood is collected to assess the rate of glomerular filtration, levels of electrolytes such as phosphates, potassium, etc., count of blood cells as well as to check the acid-base status through the level of bicarbonates in your blood.
Blood tests help assess the rate at which creatinine is cleared. If creatinine is found more than 1.4 milligrams per deciliter (mg / dL) among men, it is a symptom of a likely renal disorder. Among women, the normal level of creatinine is 1.2 milligrams per deciliter (mg / dL).Blood tests are compared with urine samples to precisely compute the excretion efficiency of kidneys. It is possible to infer the stage of a likely renal disease by assessing filtration rate as well as albumin levels in urine.
The normal filtration rate – corrected for area of body’s surface – is 125 mL per minute per 1.733 sq. m for men. For women, it is between 90 to 120 mL per minute per 1.73 sq. m. These counts are applicable to people aged less than 40 years. However, once you reach 40 years of age, your kidneys’ filtration rate begins to fall. The drop in filtration rate is estimated as nearly 1 mL per minute per year.

Blood urea nitrogen (BUN) test is also performed with blood samples. It is a test to assess the extent of nitrogen in your blood. Caveat – Intake of aspirin or a few categories of antibiotics can enhance blood urea nitrogen. As it is a by-product of protein metabolism, consumption of protein supplements can escalate its level in blood. The normal level of blood urea nitrogen stands between 8 to 20 mg / dL. When your kidneys are functioning well, blood urea nitrogen is under control. However, when the filtering efficiency of your kidneys drops, it leads to an increase in the level of blood urea nitrogen.

Imaging

Ultrasound or CT scan imaging is used to understand the functioning of kidneys. In simple terms, it involves the use of echo-waves to assess the working condition of kidneys. As it is relatively easier to scan kidneys, any changes in renal conditions can be sensed through an ultrasound scan. Kidneys follow the movement of diaphragm; so, the scan is taken either by holding your breath or while you are breathing normally.

Renal disorders can shrink the size of kidneys; hence, the scan may show smaller sized kidneys. In case of disorders-free kidneys, it is not possible to view the urine-collection part of the renal-sinus area. The echogenic properties of kidneys are compared with age. Apart from ultrasound, Doppler-based sonography is also employed to assess likely risks of perfusion. The ultrasound scan is widely depended upon to detect possible incidence of cancerous growth or stones in kidneys.

The CT scan is also used to detect abnormal renal structures. This method employs strategically positioned sources of x-rays. However, the use of a dye as a contrasting medium may not go well with people with renal disorders. In general, the CT scan is used for detecting anomalous renal structures as well as internal blockages, if any.

Renal biopsy

Biopsy of kidneys is done to detect possible abnormalities in the tissues. It is done by taking a sample of a renal tissue. The tissue is observed through a powerful microscope to study the texture and constituents of sample. A renal biopsy is recommended when your doctor aims to assess the extent of damage of kidneys. It is also performed to know the nature of a disorder and to determine the type of treatment. In a post-transplant scenario, a biopsy is done to see the reasons behind non-suitability of a transplanted kidney.

Testing procedures

Kidney function tests are done through collection of urine sample over 24 hours. A blood test is also done as part of this test panel. Urine sample test done over 24 hours can assess the discharge of creatinine – i.e., this is also called as a test to assess clearance of creatinine. Your doctor will advise you to urinate in a toilet soon after you have woken up. All further urination is done inside a container specially provided to collect samples. This sample-container needs to be closed and kept inside your refrigerator all through the sampling process. It also needs to be marked with a clear label. The next day, you need to wake up and urinate into the sample-container. With this, the sample collection process comes to an end. Ensure you have fully followed the advice of your treating doctor. The collected sample is delivered at an assigned laboratory or at your doctor’s office, as instructed.

Samples of bloods are needed to perform serum creatinine as well as blood urea nitrogen tests. The phlebotomist (sample collection agent) puts a band over the upper part of your hand. Such tightening will help the veins to be easily visible. With an antiseptic fluid, the surface area of a vein is cleaned. Blood is drawn through a needle and the container is sealed for needful processing in a laboratory. You may need to be prepared for a sharp but short prick as the needle gets under your skin. The sampled site will soon be bandaged to ensure no infections pass through it.

Chronic kidney disease – Staged

The rate of glomerular filtration is a key index. The chances of a decrease in this rate are very likely if your family’s medical history includes hypertension, diabetes mellitus, etc. Also, if you have habits like smoking and are obese, the risks can be more pronounced. Medical specialists observe that a filtration rate of above 60 mL / min / 1.73 sq. m as an adequate level. However, if the tests show a marked drop in the rate of glomerular filtration, it may serve as the first symptom of a likely renal dysfunction. Using this cue, a detailed assessment of the functioning of your kidneys needs to be done.

Early diagnosis of a renal disorder can help save your nephrons from greater damage. Such timely detection may also avoid kidney problems turning worse. Medical studies have staged renal disorders based on the glomerular rate of filtration. Stage 1 is defined when filtration rate is observed as 90 mL / min / 1.73 sq. m. The condition is labelled as stage 2 when this reading is between 60 to 89 mL / min / 1.73 sq. m. When the rate drops between values 30 to 59, it is considered as a stage 3 condition of chronic renal disorder. If the rate drops further to a range of 15 to 29, it takes a stage 4 tag. A very severe stage – i.e., stage 5 is noted to have a glomerular rate of filtration of less than 15 mL / min / 1.73 sq. m.

When the filtration rate falls below 15 mL / min / 1.73 sq. m, it is a very high risk proposition. You may need to be treated for failure of kidney function. This stage requires either a kidney transplant or regular sittings of dialysis.

Chronic kidney disease – Medications

Kidney diseases have an adverse effect on your blood pressure and vice versa; i.e., hypertension can also lead to renal disorders. Your treating doctor will treat the condition with drugs to reduce high blood pressure. The most common types of drugs prescribed for this purpose are angiotensin receptor blocking (ARB) medications, angiotensin converting enzyme (ACE) inhibiting drugs, erythropoietin catalysing medicines, etc. A few of these drugs – especially, angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blocking medicines – can also help reduce the quantum of proteins in urine. Such drugs can thus help enhance the functioning of kidneys.

Angiotensin receptor blockers (ARB)-

Irbesartan – This medication helps to keep kidneys safe from any likely damages – especially due to diabetes mellitus. It also controls the effects of a few chemicals that can shrink your blood vessels. The drug relaxes the muscles of vessels carrying blood, and thus restores normal pressure levels. This relaxation leads to supply of needful amount of blood to all parts of the body. It is widely prescribed to reduce risks associated with cardiac disorders and renal diseases.

Common side effects of this drug are nausea, drowsiness, etc. If you experience severe signs such as arrhythmia, passing out or sizeable traces of potassium in blood, you are advised to seek medical help without delay. Also, if you see any marked changes in the quantity of urine discharged, you may need to talk to your treating doctor about it.
If you have a clinical history of dehydration and hepatic disorders, you need to inform your doctor about these conditions prior to intake of these drugs. Irbesartan can interact with non-steroidal anti-inflammatory drugs such as naproxen, ibuprofen, etc. Hence, it becomes essential to tell your doctor about the drugs you already consume before starting your medication plan.

Valsartan – This drug helps reduce tension on the walls of blood vessels. This muscular easing enables a better flow of blood to the heart. It is prescribed to avoid risks associated with renal dysfunction and strokes. In very rare instances, this medicine may make your renal condition turn worse. So, if you notice the first signs of a renal damage – such as swelling of ankles, varying outputs of urine, etc. – you need to keep your treating doctor informed of such changes.

Acute side effects of this medicine include respiratory problems, extreme levels of drowsiness, rashes on skin, etc. If you live in the US, you need to call 911 upon experiencing these acute side effects. If you are living in Canada, you need to immediately get in touch with the local poison control center.
You are not advised to do activities needing excessive attention – such as operating heavy machinery or driving – especially, soon after taking this drug. Also, if you taking supplements of potassium, you need to tell your doctor about it before taking valsartan.
Valsartan can interact with drugs like lithium, a few angiotensin-converting enzyme (ACE) inhibitors as well as NSAIDs or medications taken for treating common cold.

Olmesartan – This drug is used to prevent kidney disorders, cardiac arrests and strokes by reducing your blood pressure level. It also belongs to a genre of drugs known as angiotensin receptor blocking medications. Its core function is to ease the muscles of blood vessels to enhance flow of blood. You are advised to take olmesartan as per the medication plan to get better results. However, if your pressure levels do not stabilize, you may need to tell about it to your treating doctor without delay.
Also, if you experience excessive weakness or muscular cramps, indigestion, changes in output of urine, etc., it is recommended to take needful medical attention as early as possible.

Keep your treating doctor informed of hepatic conditions (such as liver damage, cirrhosis, etc.) or renal disorders (such as an injury or damage of kidneys) before starting to take this drug. If you are taking medicines to reduce cholesterol levels – especially, resins that bind acids secreted in bile, such drugs may need to wait for at least 4 to 4.5 hours from the time you consumed olmesartan.

Angiotensin converting enzyme (ACE) inhibiting drugs

Lisinopril – This drug helps minimize risks of kidney disorders, heart problems and strokes by decreasing your blood pressure level. It is categorized under a family of medicines called as ACE inhibiting drugs. Its key function is to calm the muscles on the linings of your blood vessels, and thus help your heart to pump more blood. This function helps all parts of your body to get needful supply of blood.

Common side effects of this drug include dry spells of coughing, drowsiness, excessive weariness, etc. This drug may change the output of urine. In such instances, consult your treating doctor immediately. Also, if you are experiencing signs such as pain in abdomen, discoloration of skin or eyes (often, a yellowish tint), nausea, etc., these can be symptoms of a likely liver problem. Talk to your doctor about these signs as soon as you experience them. You need to have an open discussion with your doctor if you have more share of potassium in blood, if you are diabetic or filtering your body waste through dialysis procedures. This medicine may interact with antihypertensive drugs such as aliskiren or with medicines which increase potassium content of blood. Hence, tell your doctors about the drugs you are already taking before starting a course of lisinopril.

Captopril – This drug is taken to safeguard kidneys from damages caused by diabetes mellitus. It is also consumed to enhance the rate of survival of patients after a cardiac arrest. This drug mainly works to bring-down the level of your blood pressure. If your heartbeats are erratic or if you experience an acute spell of drowsiness, talk to your treating doctor about such severe side effects. At times, this drug may worsen your renal condition; so, if you spot signs of a likely kidney problem you need to consult your doctor. Other serious side effects of taking this medicine include itchiness, rashes on skin, inflammation of throat or face, respiratory disorders, etc. You are advised to call 911 – if you live in the US or a nearest poison control center if you are a resident of Canada.
This drug can interact with fellow-ACE inhibiting drugs as well as alcohol. It is a good practice to tell your treating doctor about your lifestyle and about the medicines you are currently taking. This medicine may alter the laboratory results of a few tests by interacting with reagents. It may also trigger an adverse side effect if taken with drugs for treating wasp or bee sting allergies.

Enalapril – It is used for the prevention of cardiac disorders – especially, problems associated with left ventricle. It helps lower your blood pressure and hence can help avoid renal problems as well as likely incidence of strokes. It is categorized under a family of drugs called as ACE inhibiting medications. Common side effects of this medication are weariness, feeling excessively dizzy, drowsiness, etc. If you notice respiratory disorders such as gasping and breathlessness, or swelling of facial organs, it is highly recommended to seek medical help as soon as possible. If you are living in the US or Canada, you are advised to contact a local poison control center without much delay. At times, this drug may trigger kidney problems. So, if you notice changes in output of your urine, you are advised to tell your treating doctor.

This drug can interact with a few angiotensin receptor blocking drugs (such as valsartan), lithium as well as with hypertensive drugs like aliskiren, etc. This medicine may also interact with cough medications and with non-steroidal anti-inflammatory drugs. It becomes important to tell your doctor about the drugs you already take before starting a course of this medication.

Drugs to stop onset of anemia

Epoetin – This is a drug based on erythropoietin, which is administered for the treatment of blood disorders such as anemia. This is widely prescribed for people living with chronic kidney disorders (CKD) as well as to people taking chemotherapy – especially, those with cancerous growth in sites other than blood cells or marrow. It is a substance that resembles natural chemicals of your body which help produce red blood cells.
It is usually administered upto thrice a week in an injection form. An apt dosage is a factor of your weight, the underlying medical condition as well as how well your body responds to the medication plan. You may need to give anytime between 3 to 7 weeks for the number of red cells in your blood to increase. Most common side effects of this drug are body pain, headache, congestion in throat, etc. It may also increase the blood pressure level in patients living with renal dysfunction. Hence, it is highly recommended to check your blood pressure levels regularly; your treating doctor may alter the dosage or prescribe anti-hypertensives if you are experiencing high blood pressure. If your clinical history has conditions such as strokes or cardiac arrests, you are advised to tell your treating doctor about them.

Darbepoetin – It is an artificial protein which helps your body to produce red cells of blood. It is prescribed for the treatment of people with chronic renal dysfunction – such as CKD, etc. It is also taken by cancer patients who are taking chemotherapeutic drugs. Most common side effects of this drug are swelling of ankles or arms, abnormal blood pressure, dry coughing spells, pain in lower abdomen, etc. Serious side effects include pain in your chest, respiratory problems such as gasping for breath, etc. Those with a prior history of cardiac arrests are advised to be extremely careful while using this drug. It is a good practice to tell your treating doctor about your family’s clinical history, especially about likely incidence of blood-clots, hypertension, epileptic convulsions, etc. It is highly recommended to contact an emergency helpline or a local poison control center if you notice any of these acute side effects.

Vitamin supplements, herbal drugs and a few over-the-counter (OTC) drugs may interact with this medication. Hence, it is essential to tell your treating doctor about existing medications taken or treatment plans pursued, if any.

Other ways to treat kidney dysfunction

A complete treatment plan includes dietary changes, provision of supplements along with drugs (such as those listed above). Among dietary changes, your dietitian may advise you to take foods with low level of salts such as potassium, phosphates and sodium. Such low-sodium and low-potassium foods help save a lot of efforts for your kidneys. As these minerals are hard to eliminate from blood, kidneys only to need to work less when you take foods with low levels of such minerals and salts. As diet plays a critical role in successful treatment, your doctor may advise you to meet a specialist. These professionals are called diet specialists for kidney care or also known as renal-care dietitians.

In general, foods with lower level of salt can help manage your blood pressure level. So, if you already have diabetes mellitus, it becomes important to keep your blood sugar level under greater control. Your doctor may also advise you to take supplements of vitamins (especially, vitamin D) as well as calcium.

If the filtration rate is very low, your doctor may advise you to opt for dialysis. There are two types of dialysis – (1) peritoneal and (2) hemodialysis. Peritoneal dialysis involves implanting a tube onto your abdomen. Treatment is carried out by passing a fluid (known as dialysate), which helps eliminate waste and drains the collected waste over a period of few hours. Hemodialysis is a mechanical device that eliminates waste from blood. A surgical procedure is needed prior to starting dialysis; a vein and artery in the upper hand are connected through an appropriate mode. You may need to come to a dialysis center for three or four times a week for dialysis sittings. Each sitting may take upto 3 hours to complete. It can also be done at night.

In sum, urinalysis is a test done to understand the functioning of kidneys. It can help detect anomalies such as stone formation in kidneys, infections in your bladder as well as chronic conditions such as renal diseases. Filtering function of kidneys can be inferred by assessing levels of proteins in urine. Those with no disorders will have very few traces of albumin in their urine.

A sample of blood is collected to assess the rate of glomerular filtration, levels of electrolytes such as phosphates, potassium, etc., count of blood cells as well as to check the acid-base status by assessing bicarbonate levels in blood.

Tests on blood samples help understand the rate of creatinine discharge. When creatinine is found in excess of 1.4 milligrams per deciliter (mg / dL) – in men and 1.2 milligrams per deciliter (mg / dL) –in women, it can be a sign of a possible kidney dysfunction.

Also, the normal rate of filtration is 90 to 120 mL per minute per 1.73 sq. m for people aged upto 40 years and less. But, as you reach 40 years, your kidneys’ filtration rate begins to decline. It may drop at a rate of 1 mL per minute each year.
Another metric to assess renal health is the blood urea nitrogen (BUN) test. It can also be assessed by testing of blood samples. Normal level of BUN is 8 to 20 mg / dL. When filtering capability of kidneys decline, an increase in the level of BUN occurs.

There are different ways to treat kidney dysfunction. It includes intake of anti-hypertensives such as angiotensin receptor blocking drugs, angiotensin converting enzyme (ACE) inhibiting mediations, drugs to boost the production of red cells of blood, etc. You may be advised to take foods low in sodium, phosphates and potassium. If the filtering rate of kidneys falls to a low level, you may be advised to opt for dialysis.
Kidney transplant surgery is an option if the filtration rate falls down to a very low level, which means the chronic condition has reached a very acute stage. Donors of kidneys for transplants can either be a recently deceased donor (from whom kidneys are harvested) or a family member (or someone) who is alive.