A basic metabolic panel, usually shortened to BMP, is one of the most common blood tests in the United States. It measures eight substances in a single sample: glucose, calcium, four electrolytes (sodium, potassium, chloride and bicarbonate) and two kidney waste products (blood urea nitrogen and creatinine). Together they show how well your kidneys filter, whether your fluid and acid-base balance is steady and what your blood sugar is doing. A single flagged value is common and often harmless, while some combinations deserve a closer look.
In this article you’ll learn what each of the eight tests means, the typical adult ranges, how a BMP differs from a comprehensive metabolic panel, how to prepare, why a result can be slightly off and when a result needs medical attention.
What a basic metabolic panel measures
According to MedlinePlus, a BMP gives information about kidney function, fluid and electrolyte balance, blood glucose, acid-base balance and metabolism. It is often part of a routine checkup, and doctors also order it for symptoms such as lasting fatigue, confusion, breathing problems or vomiting, in the emergency room and to monitor long-term conditions such as high blood pressure or kidney disease.
The 8 tests at a glance
Reference ranges differ slightly from one laboratory to another, so the range printed on your own report is the one to use. The table shows the general adult ranges published by Cleveland Clinic next to those of the MedlinePlus medical encyclopedia, which illustrates how much they can vary.
| Test | Ce qu'il reflète | Cleveland Clinic range | MedlinePlus range |
|---|---|---|---|
| Glucose | Blood sugar, the body’s main energy source | 74 to 99 mg/dL | 64 to 100 mg/dL |
| Calcium | Mineral for nerves, muscles, heart and bones | 8.5 to 10.2 mg/dL | 8.5 to 10.2 mg/dL |
| Sodium | Fluid balance, nerve and muscle function | 136 to 144 mmol/L | 136 to 144 mmol/L |
| Potassium | Heart rhythm and muscle function | 3.7 to 5.1 mmol/L | 3.7 to 5.2 mmol/L |
| Chlorure | Fluid balance, blood volume and pressure | 98 to 107 mmol/L | 96 to 106 mmol/L |
| Bicarbonate (CO2) | Acid-base (pH) balance | 22 to 30 mmol/L | 23 to 29 mmol/L |
| Azote uréique sanguin (BUN) | Protein waste cleared by the kidneys | 7 to 21 mg/dL | 6 to 20 mg/dL |
| Créatinine | Déchets musculaires éliminés par les reins | 0.58 to 0.96 mg/dL | 0.8 to 1.2 mg/dL |
Many laboratories also print an estimated glomerular filtration rate (eGFR) calculated from your creatinine, and sometimes an anion gap calculated from the electrolytes. These are not separate measurements but numbers derived from the eight results. Creatinine also depends on muscle mass, so people with more muscle, often men, can have normal values above the narrower ranges shown.
What each test on a basic metabolic panel means
Glucose
Glucose is the sugar your cells use for energy. A high level may suggest diabetes, according to MedlinePlus, while a low level can cause shakiness, sweating or confusion. The usual ranges assume you have fasted, because a recent meal raises blood sugar for a few hours. One high reading is not a diagnosis; diabetes is confirmed with repeat or additional tests. To understand the fasting number in detail, read our fasting glucose guide.
Calcium
About 1% of your body’s calcium circulates in the blood, where it supports nerves, muscles and the heart; the rest is stored in bones and teeth. MedlinePlus lists overactive parathyroid glands, certain cancers and too much vitamin D among the causes of high calcium, and low blood protein, underactive parathyroid glands, low vitamin D or magnesium and kidney disease among the causes of low calcium. Because much of the calcium in blood is carried by albumin, a low albumin can make total calcium look low. For the full picture, review our guide sur la prise de sang du calcium total.
Sodium and chloride
Sodium helps control the amount of fluid in your body and keeps nerves and muscles working, and chloride helps maintain blood volume and blood pressure, according to the MedlinePlus electrolyte panel page. The two usually move together. Dehydration, heavy sweating, kidney, heart or liver disease and medicines such as diuretics can push them out of range. Learn what a shift in sodium means by reading our guide sur le dosage du sodium dans le sang, and to see the chloride side, check our guide sur la prise de sang chlorure.
Potassium
Potassium keeps your heart beating in a steady rhythm and your muscles contracting normally. MedlinePlus notes that electrolyte imbalances can lead to serious problems such as a life-threatening irregular heartbeat, which is why doctors pay close attention to potassium. Kidney disease, some blood pressure medicines and diuretics, vomiting and diarrhea can all affect it. Potassium is also the result most often distorted by how the sample was handled, as explained further down. To see what high and low values mean, consult our guide sur la prise de sang potassium.
Bicarbonate (CO2)
The CO2 line on a BMP measures bicarbonate, the main buffer that keeps your blood from becoming too acidic or too alkaline. A low value can point to acidosis, which may occur with kidney disease, severe diarrhea or diabetic ketoacidosis, and a high value can point to alkalosis, for example after repeated vomiting. MedlinePlus explains that acidosis can cause nausea, vomiting and fatigue, while alkalosis can cause irritability, muscle twitching and tingling. Go deeper by opening our bicarbonate blood test guide.
BUN and creatinine
Blood urea nitrogen comes from the breakdown of protein, and creatinine comes from normal muscle activity. Both are removed by the kidneys, so both tend to rise when the kidneys filter less. BUN is also pushed up by dehydration, a high-protein diet and bleeding in the upper digestive tract, while creatinine depends heavily on muscle mass. Compare your numbers by exploring our BUN blood test guide et de consulter notre guide sur la créatinine dans le sang.
The eGFR printed under creatinine is the standard estimate of kidney filtration. The National Institute of Diabetes and Digestive and Kidney Diseases supports equations that do not include a race coefficient, such as the 2021 CKD-EPI creatinine equation, and notes that combining creatinine with cystatin C gives a more precise estimate. To interpret your filtration number, study our guide sur la prise de sang DFGe.
BMP vs CMP: what is the difference?
A comprehensive metabolic panel (CMP) contains everything in a BMP plus six more tests. In the words of MedlinePlus, a BMP includes 8 of the 14 tests that are part of a CMP. The extra six are albumin, total protein, bilirubin and three liver enzymes: alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
In practice, a BMP is chosen when the main questions are about kidneys, fluids, electrolytes and blood sugar, for example in the emergency room, before surgery or when monitoring a medicine that affects potassium. A CMP is chosen when the liver and nutrition also matter, such as at a yearly physical. If your report lists liver enzymes, you had a CMP; to read those extra lines, use our comprehensive metabolic panel guide.
Patterns your doctor looks for on a BMP
Doctors rarely read a BMP one line at a time. The combination of results often says more than any single value, and abnormal results are usually followed by more tests. The table shows common patterns and the explanations a doctor may consider; it is a guide to the conversation, not a diagnosis.
| Pattern on your BMP | Possible explanations to discuss |
|---|---|
| BUN high, creatinine normal or slightly high, sodium high | Dehydration, from vomiting, diarrhea, fever, heat or not drinking enough |
| BUN and creatinine both high, eGFR low | Reduced kidney filtration, sudden or long-standing; needs follow-up |
| High glucose, especially with low bicarbonate | Diabetes, or diabetic ketoacidosis when bicarbonate is low and symptoms are present |
| Low potassium and low chloride with high bicarbonate | Repeated vomiting or certain diuretics |
| Low potassium and low bicarbonate | Severe or long-lasting diarrhea |
| High potassium with high creatinine | Kidney disease or medicines that hold on to potassium; a false high from sample handling is also possible |
| Low sodium | Too much fluid, heart, liver or kidney disease, some medicines |
Dehydration is one of the most frequent reasons for an abnormal BMP and usually corrects with fluids; to recognize it, read our dehydration guide. When high glucose is the main finding, review our guide des symptômes et du traitement du diabète.
Why a BMP result can be slightly off
A value just outside the range is common and often meaningless. Cleveland Clinic points out that about 1 in 20 healthy people have a result outside the normal range, simply because ranges are built to include 95% of healthy people. Food, medicines, other health conditions and processing errors can also shift results.
- Eating before the test raises glucose above the fasting range.
- Delays between the blood draw and processing let potassium leak out of blood cells, producing a falsely high potassium.
- Blood drawn from an arm with an intravenous (IV) drip can dilute or contaminate the sample, distorting several values at once.
- Diuretics, steroids, antacids and some antibiotics can shift electrolytes, according to MedlinePlus.
- Vomiting, diarrhea and how much you drank in the previous day affect sodium, potassium, bicarbonate and BUN.
This is why a single unexpected value is usually rechecked before anything else is done.
How to prepare for a basic metabolic panel
You may need to fast for eight hours before the test, according to MedlinePlus, and Cleveland Clinic explains that fasting means having nothing but water. Your healthcare provider will tell you whether fasting is required for your test; when the BMP is drawn in an emergency or a hospital, it is done without fasting and glucose is interpreted with that in mind. Keep taking your usual medicines unless you are told otherwise, and mention any diuretics, potassium supplements or recent illness. The test is a simple blood draw, and the risks are minimal: slight pain or bruising where the needle went in, which usually fades quickly.
Quand consulter un médecin
Laboratories usually alert the ordering clinician directly when a value is in a dangerous range, so a result that reaches you through a patient portal without a call is rarely an emergency. Seek urgent care, however, if any result comes with confusion, severe weakness, a fast or irregular heartbeat, fainting, chest pain, very little urine or vomiting that will not stop. Contact your doctor soon if any of the following applies:
- Glucose above the range on more than one test, or symptoms such as strong thirst and frequent urination.
- Creatinine that has risen or an eGFR that has dropped compared with earlier results.
- Potassium or sodium outside the range, especially if you take blood pressure medicines or diuretics.
- A low bicarbonate with fatigue, rapid breathing or nausea.
- Calcium above the range, or tingling and muscle cramps with a low calcium.
A single slightly abnormal value with everything else normal and no symptoms is usually rechecked at your next visit.
Dernières avancées scientifiques
Recent studies focus less on the BMP itself than on what makes its results reliable.
Waiting too long before processing can fake a high potassium
A 2024 study drew blood from 201 volunteers and processed the tubes after different delays to mimic samples sent from a doctor’s office. After eight hours, most samples in one common type of tube showed a falsely high potassium, because potassium leaked out of blood cells while they waited. What this means for you: if a clinic sample shows a high potassium and you feel well, a quick repeat test is the usual first step.
Potassium results follow the seasons
A 2024 analysis of potassium tests from more than a million UK primary care patients found that values tend to peak in winter and dip in summer, a pattern linked to outdoor temperature that can create misleading highs and lows, and prescriptions changed in step. What this means for you: a borderline potassium during very cold or hot weather deserves a repeat before a medicine is changed.
Software that spots contaminated samples
A 2024 study applied machine learning, computer programs that learn patterns from data, to about 25.7 million BMP results to flag samples diluted by IV fluids. About three out of four flagged samples were confirmed as contaminated, and more than half had slipped past the usual checks. What this means for you: if you are in hospital and a BMP looks oddly off, contamination is a real possibility, and laboratories are starting to catch it automatically.
Kidney estimates without race
A 2025 study of nearly 15,000 Hispanic and Latino adults in the United States compared the newer race-free eGFR equation with the older one. The newer equation placed about 7% of people in a less severe kidney category and slightly lowered the share classified as having chronic kidney disease. What this means for you: your eGFR may look a little different from older reports even if your kidneys have not changed.
Fewer unnecessary daily blood tests in hospital
A 2023 systematic review, a study that pools the results of earlier research, gathered 41 studies of efforts to cut repeated daily BMP, CMP and blood count orders in hospitals. All five types of intervention usually worked, and changes to electronic ordering systems were most often highly effective. What this means for you: during a hospital stay, it is reasonable to ask whether a daily blood test is still needed.
Glossaire
| Terme | Définition |
|---|---|
| Basic metabolic panel (BMP) | A blood test that measures glucose, calcium, sodium, potassium, chloride, bicarbonate, BUN and creatinine. |
| Bilan métabolique complet | A larger panel that adds albumin, total protein, bilirubin and three liver enzymes to the BMP. |
| Électrolytes | Minerals that carry an electric charge, such as sodium and potassium, and control fluid balance and nerve and muscle activity. |
| Bicarbonate (CO2) | The main buffer that keeps blood from becoming too acidic or too alkaline. |
| Acidosis and alkalosis | Too much acid or too much base in the blood. |
| Azote uréique sanguin (BUN) | Nitrogen from urea, a waste product of protein breakdown removed by the kidneys. |
| Créatinine | A waste product of normal muscle activity removed by the kidneys. |
| eGFR | Estimated glomerular filtration rate, a calculation of how well the kidneys filter blood. |
| Pseudohyperkaliémie | A falsely high potassium result caused by how the blood sample was collected, stored or processed. |
| Gamme de référence | The range of values seen in most healthy people, set by each laboratory. |
Questions fréquentes
Do you need to fast for a basic metabolic panel?
Often, but not always. MedlinePlus says you may need to fast for eight hours, and Cleveland Clinic explains that fasting means nothing but water. Fasting mainly matters for glucose, which rises after a meal. Your provider will tell you whether your test requires it; a BMP done in an emergency room or hospital is not fasting, and the glucose result is interpreted with that in mind.
What is the difference between a BMP and a CMP?
A BMP measures 8 substances: glucose, calcium, sodium, potassium, chloride, bicarbonate, BUN and creatinine. A CMP measures those 8 plus albumin, total protein, bilirubin and the liver enzymes ALP, ALT and AST, for 14 tests in total. A BMP focuses on kidneys, fluids, electrolytes and blood sugar, while a CMP adds the liver and protein levels.
What does CO2 mean on a basic metabolic panel?
The CO2 line measures bicarbonate, the form in which most carbon dioxide is carried in the blood. It reflects your acid-base balance. A low value can point to acidosis, for example with kidney disease, severe diarrhea or diabetic ketoacidosis, and a high value can point to alkalosis, for example after repeated vomiting. Your doctor reads it together with your symptoms and other results.
Can a basic metabolic panel detect kidney disease?
It can show signs of it. Creatinine, BUN and the eGFR calculated from creatinine reflect how well the kidneys filter, and potassium and bicarbonate can change when kidney function declines. However, early kidney damage is often picked up by a urine albumin test, which is not part of the BMP. Kidney disease is diagnosed from repeated results over time, not a single panel.
Can a BMP detect diabetes?
A BMP measures glucose, so a high value can suggest diabetes. A single high reading is not enough for a diagnosis, especially if you were not fasting. Doctors confirm diabetes with repeat fasting glucose, an HbA1c test or a glucose tolerance test.
What does it mean if only one BMP value is slightly high or low?
Usually very little. Ranges are built to include about 95% of healthy people, so roughly 1 in 20 healthy people will have a value just outside the range. Food, fluids, medicines and sample handling can also shift a result. If you feel well and the other values are normal, your doctor will usually repeat the test rather than investigate further.
Sources
- MedlinePlus, National Library of Medicine — Basic Metabolic Panel (BMP) — MedlinePlus Lab Tests, updated 2024 — medlineplus.gov
- MedlinePlus Medical Encyclopedia, National Library of Medicine — Basic metabolic panel — reviewed 2025 — medlineplus.gov
- MedlinePlus, National Library of Medicine — Electrolyte Panel — MedlinePlus Lab Tests, updated 2024 — medlineplus.gov
- MedlinePlus, National Library of Medicine — Calcium Blood Test — MedlinePlus Lab Tests, updated 2024 — medlineplus.gov
- MedlinePlus, National Library of Medicine — Comprehensive Metabolic Panel (CMP) — MedlinePlus Lab Tests, updated 2023 — medlineplus.gov
- Cleveland Clinic — Basic Metabolic Panel (BMP) — Health Library, reviewed 2024 — my.clevelandclinic.org
- National Institute of Diabetes and Digestive and Kidney Diseases — Glomerular Filtration Rate Equations — NIDDK, reviewed 2025 — niddk.nih.gov
- Reuter T, Müller M, et al. — Time as a significant factor in the release of potassium from lithium heparin plasma and serum — PLoS One, 2024 — doi.org/10.1371/journal.pone.0313572
- Thayakaran R, Hotham R, et al. — Seasonal variation of serum potassium and related prescription pattern: an ecological time series — Journal of Clinical Pathology, 2024 — doi.org/10.1136/jcp-2023-208759
- Spies NC, Hubler Z, et al. — Automating the Detection of IV Fluid Contamination Using Unsupervised Machine Learning — Clinical Chemistry, 2024 — doi.org/10.1093/clinchem/hvad207
- Larkin CT, Seegmiller JC, et al. — CKD Prevalence and Incidence in Hispanic/Latino Adults Using Race-Free Estimated Glomerular Filtration Rate Equations — Kidney Medicine, 2025 — doi.org/10.1016/j.xkme.2025.101097
- Yeshoua B, Bowman C, et al. — Interventions to reduce repetitive ordering of low-value inpatient laboratory tests: a systematic review — BMJ Open Quality, 2023 — doi.org/10.1136/bmjoq-2022-002128
Pour aller plus loin
- Calculate what your electrolytes add up to by reading our guide sur le trou anionique sanguin.
- Compare your two kidney waste products by reviewing our BUN/creatinine ratio guide.
- Check the mineral that works alongside potassium and calcium by opening our guide sur l'analyse de magnésium dans le sang.
- Follow kidney health over the long term by exploring our guide sur l'insuffisance rénale chronique.
- Pair your metabolic results with a blood count by visiting our guide de la numération formule sanguine.
Comprenez vos résultats d'analyses avec BloodSense
A basic metabolic panel packs eight results onto one page, and the meaning often lies in how glucose, electrolytes, BUN, creatinine and eGFR fit together. BloodSense helps you understand each line of your BMP in plain language, with the questions worth asking your doctor. It does not make a diagnosis and does not replace your doctor.
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