Basic Metabolic Panel (BMP)

What It Is

The BMP gives a snapshot of the body's chemical balance. Electrolytes such as sodium and potassium are minerals that help control fluid levels, nerve signals, and muscle function, including the heart. Glucose is the main sugar used for energy.

BUN and creatinine are waste products that healthy kidneys filter out of the blood. Higher levels can suggest the kidneys are not filtering as well, though dehydration, diet, muscle mass, and some medications also affect them.

Because it covers several body systems at once, the BMP is used both in routine care and in hospitals and emergency settings.

Common Terminology

Electrolytes

Minerals in the blood, such as sodium, potassium, and chloride, that carry an electric charge and help control fluid and nerve function.

BUN

Blood urea nitrogen, a waste product from protein breakdown that the kidneys remove.

Creatinine

A waste product from normal muscle activity, used to assess kidney function.

eGFR

Estimated glomerular filtration rate, a calculated estimate of how well the kidneys filter blood.

Bicarbonate (CO2)

A substance that helps keep the blood's acid-base balance steady.

CMP

Comprehensive metabolic panel, which adds liver tests, albumin, and total protein to the BMP.

Why the Test Is Done

A BMP is ordered in many situations.

• As part of routine checkups or screening.
• To check kidney function and fluid balance.
• To evaluate symptoms such as confusion, weakness, vomiting, or dehydration.
• To monitor conditions such as diabetes, high blood pressure, and kidney disease.
• To monitor the effects of medications that can affect electrolytes or kidney function, such as some blood pressure medications and diuretics.
• In hospital and emergency care to get a quick overview of body chemistry.

What the Results Generally Describe

Some commonly cited adult reference ranges are listed below as general reference. Ranges and units differ between labs, and a clinician interprets individual results.

• Sodium: often about 135 to 145 mEq/L; low or high sodium can relate to fluid balance, hormones, or medications.
• Potassium: often about 3.5 to 5.0 mEq/L; both low and high levels can affect heart rhythm.
• Glucose: a fasting level of about 70 to 99 mg/dL is generally considered normal; non-fasting values are interpreted differently.
• Creatinine and BUN: higher values can be associated with reduced kidney function or dehydration; normal creatinine differs with muscle mass, age, and sex.
• eGFR: a value of 60 or higher is often described as being in the normal range, though age and other factors matter.
• Calcium, chloride, and bicarbonate help describe bone and mineral balance and the blood's acid-base status.

How the Test Is Done

A BMP uses a single blood sample.

• Blood is usually drawn from a vein in the arm.
• In hospitals and emergency departments, it may be run on a rapid analyzer.
• The eGFR is calculated from creatinine along with factors such as age and sex.
• Sometimes a BMP is repeated over hours or days to follow changes.

Preparation and What to Expect

Preparation depends on why the test is ordered.

• Fasting for several hours is sometimes requested so glucose can be interpreted as a fasting value.
• The ordering office or lab gives specific instructions.
• Dehydration, intense exercise, diet, and some medications can affect results.
• The blood draw takes a few minutes; a difficult or prolonged draw can occasionally falsely raise potassium.

When Results Are Discussed With a Clinician

Results are generally reviewed in context.

• Values outside the reference range are commonly reviewed with symptoms, medications, and previous results.
• Markedly abnormal potassium, sodium, or glucose values are generally treated as urgent.
• Changes in creatinine or eGFR over time are often followed when kidney function is a concern.
• Unexpected results are sometimes repeated to confirm them.

Questions to Ask a Healthcare Professional

General questions people often find useful to bring to an appointment:

• Should I fast before this blood test?
• Which values, if any, were outside this lab's range?
• How does my eGFR compare with earlier results?
• Could my medications or fluid intake have affected these results?
• Is a comprehensive metabolic panel sometimes ordered instead?
• How often is this panel generally repeated?

Sources

This guide was written in plain language from the following authoritative references.

1. Basic Metabolic Panel (BMP) — MedlinePlus (U.S. National Library of Medicine)
2. Blood tests — NHS
3. Kidney Tests — MedlinePlus (U.S. National Library of Medicine)

Related Guides

• TestsComplete Blood Count (CBC)What a complete blood count (CBC) measures, including red cells, white cells, hemoglobin, and platelets, and how results are generally described.
• TestsHemoglobin A1CWhat the hemoglobin A1C blood test measures, the general ADA categories for normal, prediabetes, and diabetes, and factors that affect it.
• ConditionsType 2 DiabetesGeneral information about type 2 diabetes: how it develops, risk factors, symptoms, diagnostic tests like A1C, complications, and treatment approaches.
• ConditionsHigh Blood Pressure (Hypertension)General information about high blood pressure (hypertension): what it is, risk factors, how it is measured, complications, and treatment approaches.
• Medical TermsHow to Read a Lab Report (General Guide)General guide to the parts of a lab report: test names, results, units, reference ranges, and H/L flags, and why results are interpreted by a clinician.