Kidney function tests


Kidney function tests is a collective term for a variety of individual tests and procedures that can be done to evaluate how well the kidneys are functioning. A doctor who orders kidney function tests and uses the results to assess the functioning of the kidneys is called a nephrologist.


The kidneys, the body's natural filtration system, perform many vital functions, including removing metabolic waste products from the bloodstream, regulating the body's water balance, and maintaining the pH (acidity/alkalinity) of the body's fluids. Approximately one and a half quarts of blood per minute are circulated through the kidneys, where waste chemicals are filtered out and eliminated from the body (along with excess water) in the form of urine. Kidney function tests help to determine if the kidneys are performing their tasks adequately.


The doctor should take a complete history prior to conducting kidney function tests to evaluate the patient's food and drug intake. A wide variety of prescription and over-the-counter medications can affect blood and urine kidney function test results, as can some food and beverages.


Many conditions can affect the ability of the kidneys to carry out their vital functions. Some conditions can lead to a rapid (acute) decline in kidney function; others lead to a gradual (chronic) decline in function. Both can result in a build-up of toxic waste substances in the blood. A number of clinical laboratory tests that measure the levels of substances normally regulated by the kidneys can help to determine the cause and extent of kidney dysfunction. Urine and blood samples are used for these tests.

The nephrologist uses these results in a number of ways. Once a diagnosis is made that kidney disease is present and what kind of kidney disease is causing the problem, the nephrologist may recommend a specific treatment. Although there is no specific drug therapy that will prevent the progression of kidney disease, the doctor will make recommendations for treatment to slow the disease as much as possible. For instance, the doctor might prescribe blood pressure medications, or treatments for patients with diabetes. If kidney disease is getting worse, the nephrologist may discuss hemodialysis (blood cleansing by removal of excess fluid, minerals, and wastes) or kidney transplantation (surgical procedure to implant a healthy kidney into a patient with kidney disease or kidney failure) with the patient.

Laboratory tests

There are a number of urine tests that can be used to assess kidney function. A simple, inexpensive screening test—a routine urinalysis—is often the first test conducted if kidney problems are suspected. A small, randomly collected urine sample is examined physically for things like color, odor, appearance, and concentration (specific gravity); chemically, for substances such a protein, glucose, and pH (acidity/alkalinity); and microscopically for the presence of cellular elements (red blood cells [RBCs], white blood cells [WBCs], and epithelial cells), bacteria, crystals, and casts (structures formed by the deposit of protein, cells, and other substances in the kidneys's tubules). If results indicate a possibility of disease or impaired kidney function, one or more of the following additional tests is usually performed to pinpoint the cause and the level of decline in kidney function.

There are also several blood tests that can aid in evaluating kidney function. These include:


Normal values for many tests are determined by the patient's age and gender. Reference values can also vary by laboratory, but are generally within the following ranges:

Urine tests

Blood tests

Low clearance values for creatinine indicate a diminished ability of the kidneys to filter waste products from the blood and excrete them in the urine. As clearance levels decrease, blood levels of creatinine, urea, and uric acid increase. Because it can be affected by other factors, an elevated BUN, alone, is suggestive, but not diagnostic for kidney dysfunction. An abnormally elevated plasma creatinine is a more specific indicator of kidney disease than is BUN.

Low clearance values for creatinine and urea indicate a diminished ability of the kidneys to filter these waste products from the blood and to excrete them in the urine. As clearance levels decrease, blood levels of creatinine and urea nitrogen increase. Since it can be affected by other factors, an elevated BUN alone is certainly suggestive for kidney dysfunction. However, it is not diagnostic. An abnormally elevated blood creatinine, a more specific and sensitive indicator of kidney disease than the BUN, is diagnostic of impaired kidney function.

The inability of the kidneys to concentrate the urine in response to restricted fluid intake, or to dilute the urine in response to increased fluid intake during osmolality testing, may indicate decreased kidney function. Because the kidneys normally excrete almost no protein in the urine, its persistent presence, in amounts that exceed the normal 24-hour urine value, usually indicates some type of kidney disease.

Patient education

Some kidney problems are the result of another disease process, such as diabetes or hypertension. Doctors should take the time to inform patients about how their disease or its treatment will affect kidney function, as well as the different measures patients can take to help prevent these changes.



Brenner, Barry M. and Floyd C. Rector Jr., eds. The Kidney, 6th Edition. Philadelphia, PA: W. B. Saunders Company, 1999.

Burtis, Carl A. and Edward R. Ashwood. Tietz Textbook of Clinical Chemistry. Philadelphia, PA: W.B. Saunders Company, 1999.

Henry, J. B. Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Philadelphia, PA: W. B. Saunders Company, 2001.

Pagana, Kathleen Deska. Mosby's Manual of Diagnostic and Laboratory Tests. St. Louis, MO: Mosby, Inc., 1998.

Wallach, Jacques. Interpretation of Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams & Wilkens, 2000.


National Kidney Foundation (NKF). 30 East 33rd Street, New York, NY 10016. (800)622-9020. .

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). National Institutes of Health, Building 31, Room 9A04, 31 Center Drive, MSC 2560, Bethesda, MD 208792-2560. (301) 496-3583. .


National Institutes of Health. [cited April 5, 2003]. .

National Institutes of Health. [cited June 29, 2003] .

Paula Ann Ford-Martin
Mark A. Best, M.D.

User Contributions:

How we calculate urine osmolality . what is the equation?
Simple and informative from a paients perspective. wish there were also some precautionary measures for patients listed as well. Thanks
my kid had puj obstruction. doc's sugested pyloplasty and that has been done.. the renogram result before operation was showing impared fucntion as 25% - 75% later for a followup test it showed 21% - 79% and lastly after 1 year the renal test was done and it showed 19 and 81.. what treatment would be recommended

Aga chimaobi
kidney problem has been a mproblem in many countries and we should have more nephrologist in mary parts of the world and also educate people more about the desease,
I have a blood creatinine level of 1.7. I am scheduled for hernia surgery. Any problems I need to be aware of?
Dingha sama
.I just wish to appriciate this work and to enquire if there are any journals on the relationship setween creat leveland diabetes.Thanks

i got this nephritis almost from 5 years & i hope for c cure.i know there is one ,cause there is cure for each disease in this world.GOD gave each problem with cure,time is the challenge.dear friends i hope each & everyone in this world who has a problem to be cured from it.i am very very patient with mine,forbiding my self from the most dilicious food only 2 protect my kidneys.hope all the patients get well(regards from the lovliest weather on planet - Lebanon - beirut) salam
G Srinivasa Rao
I have some kidney probs. The blood creatine level has gone up to 6. Doctor has suggested not to take any protine food. And I am following the same. Will I required to go for dialysis. For going for dialysis minimum what creatine level has to be there ?

Kindly reply.
I Thank you to all very important information you gave
I like to know the roll of electrolytes in the kidney function
thank you
Saurabh Dangre
My father is having Kidney disease.
He is on regular dialysis(twice a week),
we are taking aayrvedic and homeopathic treatment..
But, now his serum creatinine level is increase from 8 to 12.20.
plz suggest the treatment and diet for control the same
plz guide me
Very good explanation. I would like to cite this page in my paper. There is no date it was written. I can not use it in my paper.
I'm a medical student.I have a brother who is 45 years old feeling pain at the ioin region for one month specially when he bend his body. He is patient of hypertension and he takes antihypertensive drugs regularly.Recently he has done serum creatinine test and the value was 1.35gm/dl.Is it indicate kidney disiease? Which test he sholud do further?
What do the letters and word Alb/Creat ratio mean in my Renal Function tests please.also the letters eGFR mean.
many thanks

Does microscopic blood add to the level of protein that is reported on a 24 hr urine protein test?
Thanks for the help.
what are the conditions affecting the function of the kidneys??
Dear sir/ mdm

If my urine found a layer kind of syrub at the bottom of the bottle.
Does it mean I have kidney problem? My left back ard the waist sometime
can feel ached when I sit. Is it a sign of kidney problem?
Please kindly advise what I should do!
Thank you for your kind attention!

Best Regards
from india
my blood test result-
cratinine- 1.07

Please tell me the condition of my kidney.

Thank you
I have atrial fibrillation and take digoxin, warfarin, lisinopril and metoprolol. About a year ago I started to experience infrequent, sharp and sudden chest pains. The pains last only a few seconds. I am 45 years old, so I thought maybe I had a plaque build up on my arteries. I did some research and due to not having health insurance, I wanted to take a natural approach for this problem, which I thought was plaque/calcium build up. I eat a very generous amount of raw fruits and vegetables, including pomegranate concentrate, which I have been taking for about a year. Approximately two months ago I started taking 1250 mg. of EDTA along with 1000 mg. of L-Arginine a day. Less than a week ago I had some blood work done and the next day the nurse called and informed me, I need to get to the nearest emergency room because my potassium serum level is dangerously high. She wouldn't tell me over the phone what the results are. I did some research and looked into symptoms and possible causes and it seems the underlying cause could be a kidney dysfunction. I don't have any of the severe high potassium level symptoms, but I was having some about a week prior to the test. Without going into detail I believe my system got overloaded with a few toxins I was exposed to. In addition, I have herpes and just two days ago I have broken out again, perhaps due to worrying and stress. I never did go to the emergency room, but I significantly reduced my potassuim intake. I feel much better and don't have any of the symptoms I had a week prior to the blood test. I also slowed my chelation theraphy down to 625 mg. every 4 to 5 days. Any ideas on what could have been the cause of my apparent high potassium level? And since I am not having any diffculty urinating, and as I increase my water intake my urine is clearer, which is to assume my kidney function must not be severly impaired, if impaired at all, therefore did my potassium level decrease, and is it possible or as cells die and I eat more food with potassium, does it mean it will only go up, not down?
what is the significance of performing various serum & blood biochemical parameters??
My father is having Kidney disease.
now his serum creatinine level is 3.5
plz suggest the treatment and diet for control the same
plz guide me
Freguent urination during night or when cold.
I wake up 3-4 time at night. What is the cause? How to decrease the frequency?
I found this about kidney function it seems to explain it very well.
thank you for answer me about quation, can you tell me the equation of esstimation (24 hr. protein in urine collection )plz.
iam 19 year old boy living in delhi i have the problem of kidney failure .i go for dialysis twice a weak please tell me some solution for this.
I recently got a blood test done and it came back showing UREA at 7.2. I am female aged 45. What does this mean and what can I do to get it lower or is that possible?
MY MOTHER is suffering from high creatinine and uric acid,creatinine is about 12.4 and uric acid is 157.
her gfr is 19mil/min...
so please tell me the easy way for her treatment, she didn't want to do dialysis...can she improve her disease with medicines.i am very thankful t you please tell me soon.
i m getting heavy pain at kidney portion.i did sonograpy urine nd blood test also but still m getting little pain.plz give me some solution for that.thank u.
info for the kidney function test for your perusal alos for the next 24 hours it will take tototo ccl bbhytrv
what is the name of the test that mussures amount of bicarbonate?
Thank you
just a question about the kidney levels what if normal is level is at 3 what is at 4 and what does it mean for a male.

thank you very much
what is the problem if that dog blood report come? blood urea nitrogen 26 and serum creatinine 18
my father's serum cretenine level is 4.3 .please suggest me weather it can be cured by medicine and by proper diet or he should go for dylasis.
My fatehr's serum cretenine level is 2.94. please suggest me is there any treatment which can be curred by only medicines he is diabetic & High BP.he is taking treament for that for one week but is serum level is not comming doem is this is an seriuos problem. what is diet he has to take pls suggest me.
My dad recently got test results back from kidney doctor. Doctor said one result went from 1.45 from test done 6 months ago to 1.7 now. And this was not good...values going in wrong direction. I cannot remember what this test was or how serious a 1.7 was (although doctor seemed concerned). Do you know what this test may have been for? Thanks.
i have high 47 value of urea in my blood analysis , is something fishy?

sudesh khokAR
hi friends
The normal Creatinine TEST RESULTS should be min - 0.6, max 1.5( NORMAL HUMAN BODY )
my father having a kidney problem... today his test result have increased from 1.8 to 3.04..
really .. i was shocked by seeing this ...


can any one suggest any measures to be taken.. about the the food .. what is the best food menu to control this .. ANY SUGGESSIONS PLZ SEND IT TO MY MAIL ID ..
If report show 1.7 & diabitic patient what is liquid intake limit in ml.,

& type of food intake
What if diabetic patient having creatinine report
1.7 ? What food can be taken & is there any liquid intake
Limitation in ml.
Hi evryone
My name is serene, am from canada. My husband has been sick for the past 11yrs now and the doctor demand that my husband needs surgery, that his kidney is bad and he need a kidney transplant. so just 2weeks ago a family relation introduce a female spell caster online ( to that did a spell for my husband's health. she casted the spell and also sent a potion and a soap for my husband to bath with for 3good days.
The greatest miracle that happened was my husband wakeup on the 3rd day morning very bright and he said he is feeling different and strong.
when we went for checkup, the doctor was surprised and was asking several questions.
right now as i write, my husband is well and health just as the Priestess Munak has mention.
I cant thank her enough for restoring my husband's health and bringing our family together.
Godbless you priestess munak.
I would also want you to meet her just as i did with faith on

My 88 years old father's blood test result-

Creatonin= 1.7
Potassium =4

Could you please tell me the condition of his kidney. How dangerous it is?

Thank you in advance,
hi i am nany from india , my mother is sick from last many the doctor declair her an an orthropores patient.after taking lots of medicens now she did some tests & reports shows high creatinine level=1.19 ;uric acid=4.60 and protein=7.84 which is higher than normal rang.
could u please tell me the condition of his kidney. how dangerous it is
I am very greateful for the informative content of this article.
my mother in laws test results are cr493 and urea 9803 help please
amit kumarc das
hi,my problem, 24 hour urine protein test result 1100mg.cretin=.7
so,please help me.
My clinic called with my blood and urine results concerning my kidney disease. Their numbers don't come close to matching anything I've found on the Internet. Maybe someone can help? Here's what they told me:

Microalbumin: Normal 0-17, Mine is 27

Creatinin 1: Normal 22-32, Mine is 40.1

Creatinin 2: Normal 0-30, Mine is 67.3

Nurse didn't explain difference in the two Creatinin tests. If anyone can make sense of this, please let me know. Thanks.
my aunt test results ain't good ,creatinin was coming out to be 23.
Dialysis is recommended.Please help me out.Thanks
out of ten symptoms of kidney disease given seven are experienced on my body plz advice me
hi its salman here well i just asking to u dr sir my mother blood test is not well coz her blood ure is 142mgl please in this type of case what we do. becouse sir her potasiam test is hight please you guide me what we do thanx..
Slow and steady pranayam (inhalation & exhalation) is very useful kidney problems. Specially anulom - vilom pranayam
My urea level is 17.2. & creatine is 1.1 BUN 8.5 . Are my kidneys normal?
Sir my child age 1years old son.Her body condition bad.then the doctor said her ceeation level is to reduce the creatine level.
What should be test result at the kidney failure for the following: Creatinine, Sodium, Potassium, Urea, GFR, AKI..??
Jeannifer Trimor
Hello. Is 7.2 in my blood chem safe for a woman like me with a high as 210 triglycerides in the result? I have a feeling of discomfort from my abdomen. Please answer it.. I will wait for your response. thank you. God speed.
I'm aged 17 my blood urea level is 32mg/dl
S.creatinine level is 1.2mg/DL
S.uric acid level is 6.5mg/DL
Blood glucose level is 70 mg/DL
Whether these levels are normal?
Latoya Delorenzo
My colleagues needed SSA-3373-BK some time ago and came across a website that hosts lots of fillable forms . If others need SSA-3373-BK too , here's and here
I am 36year old i had HP past 4yrs and creatinen level of 1.64.How many percent of kidneys function
Sanjay Panda
Sir- I am 38 years male, my blood urea lebel is 20 mg and S. Creatinine is 2.1mg/dl then after 5 days again i test S. Creatinine is 1.2 mg/dl please suggest my Kidney function is well or not if not pls suggest Diagnosis.
kumar gaurav
My creatinine level is 4.3 , plzz suggest me how much my kdney damage
My Creatinine level is 1.12mg/dl , Serum Urea 28.00mg/dl, Serum Uric acid 5.60mg/dl , Blood Sugar (fasting) 87.00mg /dl.
I am 52 years old hypertensive but BP remains normal while taking Atenolol 25mg along with Enarapril 10 mg daily. I have been taking the ACE inhibitor for the lat 23 years regularly but it was initially 5mg daily.
My weight seems to be heavy and it is around 87 kg with my height 5 feet 7 inches. I think it ought to be below 70 kg but despite several attempts I failed to reduce the same.
My triglyceride level is 137 mg/dl ; Cholesterol 118 mg/dl, HDL 30,LDL 64, VLDL 24 mg/dl.
Now my questionis whether I should consult Nephrologist ? or to shift to Amlodepin from Enarapril ?
Hi every one. Yesterday my doc advice me to do some test. The reports show S creatinine is 1.35. I have hypertension. Doc say kidney problem. Please some one suggest me.
in my father blood result is 3.4 creatinine and urea is 84.3mg/dl at 18 juiy 2014.taking some medicine after some time(24.09.2014) taken treatment his creatinine and urea 2.9 and 59. After then he some month left medicine then again creatinine level become high 7.86 and urea 104.60. then start dialysis and through biospy doctor tell disease name is membranous nephropathy .at this time my father is dialysis. what is the best treatment for my father ??.
Noman Shaikh
it is very interesting info about Kidneys.
it's helpful for us..
My girl child of age 2 years has blood urea level 36mg/dl ,is it normal for her

Comment about this article, ask questions, or add new information about this topic: