Metabolic panel components: what each BMP and CMP line measures
A basic metabolic panel (BMP) lists eight lines: glucose, calcium, the electrolytes sodium, potassium, chloride and carbon dioxide, and the kidney-related lines urea nitrogen (BUN) and creatinine. A comprehensive panel (CMP) adds six: albumin, total protein, ALP, ALT, AST and bilirubin. This guide says what each line measures, not what a value means.
Not medical advice. This guide describes what the parts of a lab report are and how they are recorded. It does not say what any result means for a person, and it does not recommend treatment, supplements or targets.
What the two panels list
Both panels come from one blood sample. Glucose is the sugar concentration in the blood. Sodium, potassium and chloride are dissolved salts, called electrolytes, and carbon dioxide on this panel is the total, mostly bicarbonate. Calcium is a mineral. BUN and creatinine are waste products carried in blood: BUN is the nitrogen in urea, and creatinine comes from muscle metabolism.
The extra CMP lines describe proteins, enzymes and a pigment. Albumin is the main protein in blood plasma, and total protein adds the globulins to it. ALP, ALT and AST are enzymes reported by their activity, in U/L. Bilirubin is a yellow pigment formed when red cells are broken down.
Reports often add calculated lines: eGFR, estimated from creatinine with an equation that uses age and sex, the BUN/creatinine ratio, the anion gap, globulin (total protein minus albumin) and the albumin/globulin ratio. A footnote may name the equation.
Recording a metabolic panel
Five steps.
Copy the panel name
Write down BMP, CMP or the printed panel title. It tells you which lines to expect and whether any are missing.
Keep names and units together
BUN is usually in mg/dL and urea in mmol/L, and they are not the same number. Creatinine appears in mg/dL or µmol/L. Record each as printed.
Mark the calculated lines
eGFR, the BUN/creatinine ratio, the anion gap, globulin and the albumin/globulin ratio are derived. Copy the equation named in a footnote, if there is one.
Keep signs on values
eGFR is often printed as >60 instead of a number. The sign belongs to the value, so copy it rather than typing 60.
Keep the bands
Many lines print separate ranges for men and women or by age. Record the band that was printed for the sample, or keep the text.
BMP and CMP lines
Eight lines in a BMP; all of them plus six more in a CMP.
| Line | What it measures | Panel | Units you may see |
|---|---|---|---|
| Glucose | The sugar concentration in the sample | BMP, CMP | mg/dL, mmol/L |
| Calcium | Total calcium in blood | BMP, CMP | mg/dL, mmol/L |
| Sodium, potassium, chloride | Dissolved electrolytes | BMP, CMP | mmol/L, mEq/L |
| CO2 or bicarbonate | Total carbon dioxide, mostly bicarbonate | BMP, CMP | mmol/L, mEq/L |
| BUN or urea | The nitrogen in urea (BUN), or urea itself | BMP, CMP | mg/dL for BUN, mmol/L for urea |
| Creatinine | A muscle-derived waste product in blood | BMP, CMP | mg/dL, µmol/L |
| Albumin, total protein | The main blood protein, and all proteins together | CMP | g/dL, g/L |
| ALP, ALT, AST | Enzyme activity in the sample | CMP | U/L, IU/L |
| Bilirubin | A pigment formed from the breakdown of red cells | CMP | mg/dL, µmol/L |
| eGFR | An estimate calculated from creatinine, age and sex | Often added | mL/min/1.73 m² |
| Other calculated lines | BUN/creatinine ratio, anion gap, globulin and albumin/globulin ratio: each derived from other lines on the report | Often added | Mixed; ratios have no unit |
What goes wrong
Most come from lines that look alike but are not.
- Treating BUN and urea as one number. BUN counts the nitrogen in urea, in mg/dL. Urea is reported in mmol/L. Record which one the report gives.
- Reading CO2 as a gas. On a metabolic panel it is total carbon dioxide in the sample, mostly bicarbonate. It is not a breathing measurement.
- Dropping the sign on eGFR. A value printed as >60 is not 60. Keep the sign.
- Mixing total and ionised calcium. A report may list either. They are different lines, and a factor for one is wrong for the other.
- Counting calculated lines as extra measurements. Globulin, the anion gap and the BUN/creatinine ratio come from other lines on the same report.
- Dropping the label on glucose. Glucose can print as fasting, random or plain. BioPanel gives them all the name Glucose and keeps the printed name beside it, so copy that wording. See fasting and collection notes.
- Missing page two. A CMP has at least fourteen lines, and the later ones, with footnotes, can continue on the next page.
How BioPanel helps
BioPanel recognises these lines by name: Glucose, Calcium, Sodium, Potassium, Chloride, Bicarbonate (also printed as CO2), BUN, Urea, Creatinine, eGFR, Albumin, Total protein, Globulin, ALP, ALT, AST and Bilirubin. Lines it does not recognise, such as the anion gap, are still returned under the printed name. A lab report PDF or photo gives one row per line; values such as >60 keep their sign, ranges with sex or age bands are kept as text and left uncompared, and BUN and urea stay in their printed units. Free: 1 file per day, up to 10 pages, no account. Files over 10 pages are converted up to page 10 on the free allowance; a page code converts the whole file, up to 150 pages. See pricing.
Questions people ask
What is the difference between a BMP and a CMP?
A basic metabolic panel lists eight lines. A comprehensive panel adds six more: albumin, total protein, ALP, ALT, AST and bilirubin. Both come from one blood sample.
What does CO2 mean on a metabolic panel?
It is total carbon dioxide in the blood sample, mostly bicarbonate. It is not a measure of breathing, and some reports label the line bicarbonate instead.
Is BUN the same as urea?
Not as printed. BUN counts the nitrogen in urea and is usually in mg/dL, while urea is reported in mmol/L. The numbers differ, so record which one the report gives.
Which lines are calculated?
Commonly eGFR, the BUN/creatinine ratio, the anion gap, globulin and the albumin/globulin ratio. They are derived from other lines on the same report, and a footnote may name the equation.
Why is eGFR sometimes printed as >60?
Some labs print a limit instead of a number above a stated cutoff. The sign matters, so keep it with the value rather than typing a bare number.
Does a metabolic panel tell me what my results mean?
No. This guide describes what each line measures. What a value means for you is for a clinician who knows your history. This is not medical advice.