What is the BUN/Creatinine Ratio?
The Blood urea nitrogen (BUN): Creatinine Ratio [BUN/Creatinine Ratio] is a renal (related to kidneys) function indicator, commonly used to diagnose acute or chronic renal (kidney) disease or damage.
Blood Urea Nitrogen (BUN) and creatinine are both waste products of normal metabolism in the human body.
BUN represents the amount of nitrogen produced from the metabolism of proteins.
Creatinine is a normal waste product of muscle.
Once a person performs both a BUN and Creatinine test, doctors can use the combined results to find the BUN-to-creatinine ratio. The BUN and creatinine tests alone are excellent methods of testing liver and kidney health, but together, doctors get a much better understanding of your kidney health and can provide a more accurate diagnosis to kidney-related issues.
Most clinicians agree that creatinine is a more specific indicator of glomerular function than BUN. However, the BUN to creatinine ratio may be used as an indirect estimate of renal function.
Note: If results for BUN and Creatinine are both within the normal reference range, the BUN/Creatinine ratio will not be reported (not applicable).
What is a BUN test?
A Blood Urea Nitrogen (BUN) test measures the amount of nitrogen in your blood, and is used to provide doctors with information on how well your kidneys and liver are functioning. The nitrogen comes from the waste product urea, which is converted from nitrogen and produced in the liver when protein is metabolized after eating. Healthy kidneys then filter the urea and remove other waste products like urea through urination. It is normal to have some urea present in the blood since your liver is always producing it, but too much may indicate an issue with your kidneys.
What is a Creatinine test?
Creatinine is another type of molecule that is generated from muscle metabolism. Like urea, creatinine is transported through the bloodstream and to the kidneys, where it is also filtered and excreted through the urine. The rate of creatinine formation depends on the individual’s muscle mass. Because muscle mass remains fairly consistent, creatinine levels remain essentially unchanged throughout the day. When results of a creatinine test reveal excess amounts, it could signify impaired kidney function or kidney disease.
Why are we measuring the BUN/Creatinine ratio?
The BUN/Creatinine ratio blood test is used to diagnose acute or chronic renal (kidney) disease or damage. It may also be used to determine gastrointestinal bleeding or trauma. BUN (blood urea nitrogen) and creatinine are both filtered in the kidneys and excreted in urine. The two together are used to measure overall kidney function.
The BUN/Creatinine ratio provides specific clinical information about the kidney that can be used for multiple purposes. The BUN/Creatinine ratio is obtained to assess normal kidney function, help identify possible kidney diseases, to monitor the progression of kidney disease, or to monitor the effectiveness of medications in treating kidney disease.
The BUN/Creatinine ratio is useful in the differential diagnosis of acute or chronic renal disease. Reduced renal perfusion, e.g., congestive heart failure, or recent onset of urinary tract obstruction will result in an increase in BUN/Creatinine ratio. Increased urea formation also results in an increase in the ratio, e.g., gastrointestinal bleeding, trauma, etc. When there is decreased formation of urea as seen in liver disease, there is a decrease in the BUN/Creatinine ratio. In most cases of chronic renal disease the ratio remains relatively normal.
Basic on your kidneys:
You have two kidneys, each about the size of an adult fist, located on either side of the spine just below the rib cage. Although they are small, your kidneys perform many complex and vital functions that keep the rest of the body in balance.
For example, kidneys:
- Help remove waste and excess fluid
- Filter the blood, keeping some compounds while removing others
- Control the production of red blood cells
- Make vitamins that control growth
- Release hormones that help regulate blood pressure
- Help regulate blood pressure, red blood cells, and the amount of certain nutrients in the body, such as calcium and potassium.
BUN and creatinine are two metabolites steadily produced in the body.
The Blood Urea Nitrogen (BUN) level is a reflection of the amount of protein breakdown in the blood and it will accumulate with kidney malfunction. Creatinine is a breakdown product of muscle metabolism. It will also accumulate in the blood with kidney malfunction.
BUN is filtered in the nephrons and then reabsorbed in the blood, whereas creatinine is filtered and then secreted by the tubular cells into the tubular lumen.
Each of your kidneys is made up of about a million filtering units called nephrons. Those are the functional units of the kidney. They perform the filtering of the blood. Each nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process: the glomerulus filters your blood, and the tubule returns needed substances to your blood and removes wastes.
What is acute renal failure (ARF)?
Acute renal failure (ARF), also known as acute kidney injury (AKI), is a sudden episode of kidney failure or kidney damage that happens within a few hours or a few days. AKI causes a build-up of waste products in your blood and makes it hard for your kidneys to keep the right balance of fluid in your body. ARF can also affect other organs such as the brain, heart, and lungs. Acute kidney injury is common in patients who are in the hospital, in intensive care units, and especially in older adults.
What are the signs and symptoms of acute kidney injury?
Signs and symptoms of acute kidney injury differ depending on the cause and may include:
- Too little urine leaving the body
- Swelling in legs, ankles, and around the eyes
- Fatigue or tiredness
- Shortness of breath
- Confusion
- Nausea
- Seizures or coma in severe cases
- Chest pain or pressure
In some cases, AKI causes no symptoms and is only found through other tests done by your healthcare provider.
What are normal levels:
The ratio of BUN to creatinine is usually between 10:1 and 20:1.
A healthy individual typically has serum BUN levels higher than serum creatinine levels. A measurable increase in the serum creatinine levels in hospitalized patients is indicative of Acute renal failure (ARF).
Differentiating Acute renal failure (ARF) into 3 categories (prerenal, intrinsic renal, and postrenal failure) is of significant clinical utility.
→ BUN/Creatinine Ratio between 10 and 20 is considered a normal value or may be suggestive of a post-renal cause of ARF.
→ High BUN/Creatinine Ratio (>20) may be suggestive of a pre-renal cause of AFR.
→ Low BCR (<10) may be suggestive of an intrinsic renal cause of AFR.
What is the BUN/Creatinine ratio used for?
Looking at the BUN/Creatinine ratio can further aid in distinguishing which disease state may be causing abnormal lab values. The BUN/Creatinine ratio usually remains normal in chronic kidney disease. A BUN:creatinine ratio that is >20 suggests dehydration or another state that causes decreased renal perfusion.
A BUN:creatinine ratio >30 can suggest a GI bleed.
One may look at the BUN / Creatinine ratio to help determine the cause of renal failure. The ratio of BUN to creatinine is usually between 10:1 and 20:1. An increased ratio may be due to a condition that causes a decrease in the flow of blood to the kidneys, such as CHF (=Congestive Heart Failure) or dehydration. It may also be seen with increased protein, from BI bleed, or increased protein in the diet. The ratio may be decreased with liver disease (due to a decrease in the formation of urea) and malnutrition.
Reference Range(s):
| Bun/Creatinine Ratio | 6-22 (calc) | ||||
| Urea Nitrogen (BUN) | |||||
| Age | Male (mg/dL) | Female (mg/dL) | |||
| <1 Month | 4-12 | 3-17 | |||
| 1-11 Months | 2-13 | 4-14 | |||
| 1-3 Years | 3-12 | 3-14 | |||
| 4-19 Years | 7-20 | 7-20 | |||
| ≥20 Years | 7-25 | 7-25 | |||
| Creatinine | ||
| Age | Male (mg/dL) | Female (mg/dL) |
| ≤2 days | 0.79-1.58 | 0.79-1.58 |
| 3-27 days | 0.35-1.23 | 0.35-1.23 |
| 1 month-9 years | 0.20-0.73 | 0.20-0.73 |
| 10-12 years | 0.30-0.78 | 0.30-0.78 |
| 13-15 years | 0.40-1.05 | 0.40-1.00 |
| 16-17 years | 0.60-1.20 | 0.50-1.00 |
| 18-19 years | 0.60-1.26 | 0.50-1.00 |
| 20-49 years | 0.60-1.35 | 0.50-1.10 |
| 50-59 years | 0.70-1.33 | 0.50-1.05 |
| 60-69 years | 0.70-1.25 | 0.50-0.99 |
| 70-79 years | 0.70-1.18 | 0.60-0.93 |
| ≥80 years | 0.70-1.11 | 0.60-0.88 |
For patients >49 years of age, the upper reference limit for creatinine is approximately 13% higher for people identified as African-American.
Linked Sources:
https://www.kidney.org/atoz/content/AcuteKidneyInjury
https://www.webmd.com/a-to-z-guides/blood-urea-nitrogen-test
References:
Uchino S, Bellomo R, Goldsmith D. The meaning of the blood urea nitrogen/creatinine ratio in acute kidney injury. Clin Kidney J. 2012 Apr;5(2):187-191. doi: 10.1093/ckj/sfs013. PMID: 29497527; PMCID: PMC5783213.
Salvador LG, Carolina GF, Jesús RD, Virgilia SAM, Susana RA, Jonathan CÍ, Luis SPJ, Claudio R. A low BUN/creatinine ratio predicts histologically confirmed acute interstitial nephritis. BMC Nephrol. 2023 Mar 27;24(1):75. doi: 10.1186/s12882-023-03118-0. PMID: 36967386; PMCID: PMC10041724.
Sujino Y, Nakano S, Tanno J, Shiraishi Y, Goda A, Mizuno A, Nagatomo Y, Kohno T, Muramatsu T, Nishimura S, Kohsaka S, Yoshikawa T; West Tokyo Heart Failure Registry Investigators. Clinical implications of the blood urea nitrogen/creatinine ratio in heart failure and their association with haemoconcentration. ESC Heart Fail. 2019 Dec;6(6):1274-1282. doi: 10.1002/ehf2.12531. Epub 2019 Dec 9. PMID: 31814319; PMCID: PMC6989280.
Shen S, Yan X, Xu B. The blood urea nitrogen/creatinine (BUN/cre) ratio was U-shaped associated with all-cause mortality in general population. Ren Fail. 2022 Dec;44(1):184-190. doi: 10.1080/0886022X.2022.2030359. PMID: 35166184; PMCID: PMC8856064.
Ok F, Erdogan O, Durmus E, Carkci S, Canik A. Predictive values of blood urea nitrogen/creatinine ratio and other routine blood parameters on disease severity and survival of COVID-19 patients. J Med Virol. 2021 Feb;93(2):786-793. doi: 10.1002/jmv.26300. Epub 2020 Jul 22. PMID: 32662893; PMCID: PMC7405288.
Hosten AO. BUN and Creatinine. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd ed. Boston: Butterworths; 1990. Chapter 193. PMID: 21250147.
Matsue Y, van der Meer P, Damman K, Metra M, O'Connor CM, Ponikowski P, Teerlink JR, Cotter G, Davison B, Cleland JG, Givertz MM, Bloomfield DM, Dittrich HC, Gansevoort RT, Bakker SJ, van der Harst P, Hillege HL, van Veldhuisen DJ, Voors AA. Blood urea nitrogen-to-creatinine ratio in the general population and in patients with acute heart failure. Heart. 2017 Mar;103(6):407-413. doi: 10.1136/heartjnl-2016-310112. Epub 2016 Sep 22. PMID: 27658757.
Keeping track of your medical data and laboratory results while understanding what they mean empowers positive health outcomes.
Keeping track of your medical data and lab results while understanding what they mean empowers positive health outcomes.
Save 10% off any plan with promo-code:
HEALTH10
The BUN/Creatinine ratio is useful in the differential diagnosis of acute or chronic renal disease.
→ An increased ratio of BUN to creatinine may be due to conditions that cause a decrease in the flow of blood to the kidneys, such as congestive heart failure or dehydration. Congestive heart failure is a long-term condition that happens when your heart cannot pump blood well enough to give your body a normal supply. Blood and fluids collect in your lungs and legs over time.
→ Reduced renal perfusion, e.g. recent onset of urinary tract obstruction, will result in an increase in BUN/Creatinine ratio. Urinary tract obstruction is a blockage that inhibits the flow of urine through its normal path (the urinary tract), including the kidneys, ureters, bladder, and urethra. Blockage can be complete or partial. Blockage can lead to kidney damage, kidney stones, and infection.
→ An increased ratio of BUN to creatinine may also be seen with high protein blood levels or from gastrointestinal bleeding, trauma. etc.
Elevated Blood Urea Nitrogen (BUN)/Creatinine ratios can stem from various factors, including dehydration, which impairs kidney function by reducing blood flow, thereby concentrating waste products. It's essential to maintain adequate hydration to mitigate this. Additionally, kidney disease, both acute and chronic, can lead to higher BUN/Creatinine ratios, necessitating a holistic management approach that encompasses dietary modifications and lifestyle changes. A high protein diet, another contributing factor, increases urea production, thus elevating the ratio, emphasizing the need for a balanced diet. Certain medications like corticosteroids are also known to affect BUN/Creatinine levels, requiring regular medication review and adjustments. A comprehensive approach to kidney health involves adopting a kidney-friendly diet that limits sodium, potassium, and phosphorus while ensuring moderate, high-quality protein intake. This diet, coupled with lifestyle practices like regular exercise and stress management, supports kidney function.
Sign up
Sign up now and create your account. Use code HEALTH10 for a 10% discount on any plan. Don't miss out!
Organize
Bring all results from any laboratories to your account. You can enter your tests yourself, or we'll be happy to organize your files—whether in PDF, JPEG, CSV, or even screenshots.
Learn and improve
Once your information is stored in your account, dive into a wealth of insights about your results. If you have any more questions, we are here to answer them.
A low BUN/Creatinine ratio can be indicative of several underlying conditions.
Some potential causes include:
→ Low protein intake: This could be due to malnutrition or starvation, which results in lower production of BUN.
→ Advanced liver disease: Impaired liver function can lead to decreased urea production, lowering BUN levels.
→ Sickle cell anemia: This condition can lead to decreased reabsorption of urea by the kidneys.
→ Hypothyroidism: Low thyroid hormone production can lead to increased creatinine levels.
→ Rhabdomyolysis: Muscle breakdown leads to elevated creatinine levels.
→ Kidney damage or failure: Impaired kidney function can cause an increase in blood creatinine levels.
→ Use of certain drugs: For instance, acetazolamide can affect BUN/Creatinine ratio.
It's important to work with a healthcare professional for an accurate diagnosis as this ratio is only one indicator and should be interpreted in the context of overall health and other test results.
Guiding our user for 10 years to promptly understand, track, and act on their laboratory results.
$15/month
for personal lab results
Cancel your subscription at any time.
$250/once
full premium version
$45/month
track your clients’ labs
Cancel your subscription at any time.
Guiding our user for 10 years to promptly understand, track, and act on their laboratory results.
Personal plans
track personal results
Professional Plan
track multiple client's results
$15/month
for personal lab results
$250/once
own it for life
$45/month
for health professionals
Complete Plan
Unlimited Plan
$15 per month
$250 full version
Are you a health professional?
Level up your lab report analysis with our Pro plan, built for health practitioners like you.
Health Business Account
$45/month
Cancel your subscription at any time.
Unlock additional Pro plans when you sign up.
Unlock Your Health Journey with Healthmatters.io! Ever wished for a one-stop digital health haven for all your lab tests? Look no further! Healthmatters.io is your personalized health dashboard, bringing together test reports from any lab. Say goodbye to scattered results—organize and centralize your lab data effortlessly. Dive into the details of each biomarker and gain insights into the meaning behind your medical test data.
Join the community of thousands who've transformed the way they understand their lab results. Experience the joy of having all your lab data neatly organized, regardless of where or when the tests were done.
For our professional users, Healthmatters.io is a game-changer. Revel in the intuitive tools that not only streamline analysis but also save valuable time when delving into your client's lab report history. It's not just a dashboard; it's your gateway to a smarter, more informed health journey!
Healthmatters.io personal account provides in-depth research on 4000+ biomarkers, including information and suggestions for test panels such as, but not limited to:
You can combine all test reports inside your Healthmatters account and keep them in one place. It gives you an excellent overview of all your health data. Once you retest, you can add new results and compare them.
If you are still determining whether Healthmatters support your lab results, the rule is that if you can test it, you can upload it to Healthmatters.
While we do talk about popular labs, we welcome reports from lots of other places too. It's as simple as this: if you can get a test done, you can upload it to Healthmatters. We can interpret results from any lab out there. If laboratories can analyze it, we can interpret it.
Still on the hunt for a specific biomarker? Just tell us, and we'll add it to our database. Anything from blood, urine, saliva, or stool can be uploaded, understood, and tracked with your Healthmatters account!
There are two ways to add your test reports to your healthmatters.io account. One option is to input the data using the data entry forms. The other method is to utilize our "Data entry service."
Our data entry forms offer an easy, fast, and free way for you to input the reports yourself. Self-entry allows you to add an unlimited number of reports at no cost. We make the self-entry process user-friendly, providing dozens of templates that pre-populate the most popular laboratory panels and offering instant feedback on entered values.
For those who prefer assistance, we offer a "Data entry service" to help you input your data. Simply attach an image or file of your lab test results, and a qualified team member from our data entry team will add the results for you. We support various file types, including PDFs, JPGs, or Excel. This service is particularly useful if you have many reports to upload or if you're too busy to handle the data entry yourself.
Our special data entry service makes it easy to add your results to your private dashboard. Just attach an image or a file of your lab test results, and our skilled data entry team will do the work for you. It's all done by humans, ensuring that your data is entered accurately and with personal care for each client.
Depending on your account, the data entry service can be included for free or come at an additional cost of $15 per report.
For users on the Complete monthly plan, the first report is entered free of charge, and each additional report incurs a fee of $15.
Unlimited account holders enjoy the entry of ten reports without charge. Subsequent reports are subject to a $15 fee per report.
Additionally, users on the Complete plan can upgrade to a yearly subscription from the account settings. The annual subscription includes a data entry service for five reports.
The Unlimited plan is a one-time purchase for $250, and it covers your account for a lifetime with no additional payments.
For the Complete plan, the cost is $15 per month. You have the flexibility to cancel it anytime through your account settings, ensuring no further payments. To avoid charges, remember to cancel at least a day before the renewal date. Once canceled, the subscription remains active until the end of the current billing cycle.
Additionally, you can upgrade to the yearly Advanced plan from within your account. The annual cost is $79, and it comes with a data entry service for five reports.
You can always upgrade to a lifetime version with a prorated price from a monthly or yearly subscription.
Simply log in and navigate to your account settings to cancel your subscription. Scroll down to locate the 'Cancel' button at the bottom of the page. Ensure you cancel at least one day before the renewal date to prevent any charges. Once cancellation is requested, the subscription remains active until the conclusion of the current billing cycle.
Unlocking the insights from your lab tests has never been this intuitive! We've crafted multiple ways for you to navigate your data, whether you're glancing at a single report or delving into a treasure trove of testing data.
1. Graph View:Dive into a visual journey with our biomarker graphs, showcasing over 40 data points. Combining years of results unveils trends, empowering you to make informed decisions. Our visualization tools make it a breeze to compare and understand changes over time, even if your results are from different labs. A search function and filters simplify the exploration of extensive data, allowing you to focus on what needs attention.
2. All Tests ViewGet a quick grasp of your test reports in minutes! Explore neatly organized reports on a timeline, highlighting crucial details like dates, critical results, and lab/panel names. Each report opens up to reveal in-depth descriptions and additional recommendations for each biomarker. The history of previous results is just a click away, and you can download a comprehensive report for deeper insights. Color-coded and user-friendly, it's designed for easy reading, understanding, and navigation.
3. Table View:For a holistic view of all biomarkers side by side, our table view is your go-to. Results are neatly displayed in a categorized and dated table, ideal for those with an extensive test history. Utilize sorting, filters, and color-coding to enhance your analysis and gain extra insights.
Experience the power of clear, organized data visualization with Healthmatters.io — your key to understanding and taking charge of your health journey!
Yes, you can download information from your account. We can compile your labs into a CSV file. To download all your labs, you can go to Account Settings, and at the bottom of the page, you will find a link to download your information.
Yes, you can print your report. To do so, navigate to "All tests" and open the report you wish to print. You'll find a print button in the right corner of the report. Click on it, and your browser's print window will open. If you prefer to print in a bigger typeface, adjust the scale using the print window settings.
A personal account is all about keeping your own lab test results in check. It's just for you and your personal use.
The professional or business account is designed for health professionals who wish to track and organize their clients' laboratory results.
To learn more about Healthmatters Pro, please refer to the professional page.
At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.
Alanine-aminotransferase (ALT, SGPT), Albumin, Serum, Albumin/Globulin (A/G) Ratio, Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST, SGOT), Bilirubin Total, Blood urea nitrogen (BUN), BUN/Creatinine Ratio, Calcium, Serum, Carbon Dioxide (CO2), Chloride, Serum, Creatinine, Serum, eGFR - Estimated Glomerular Filtration Rate (African Am), eGFR - Estimated Glomerular Filtration Rate (Non-African Am), eGFR / Cystatin C, Globulin, Serum (aka Globulin, Total), Glucose, Glucose Non-Fasting, Intestinal Isoenzymes (Alkaline Phosphatase), Potassium, Serum (Kalium), Sodium, Serum (Natrium), Total Protein, Serum
