Metabolic Panel: BMP & CMP Nursing Lab Values

As a nursing student or nurse you want to be very familiar with the metabolic panel. The metabolic panel can be ordered as either a basic metabolic panel (BMP) or comprehensive metabolic panel (CMP). This review is part of a “Lab Values for Nurses” series.

Why is it so important to know about a BMP or CMP? This blood test is a very common test ordered on a patient in the hospital and is just as common as the CBC (which we discussed in the previous review).

What do you need to know about the metabolic panel for exams and as a nurse?

• What the metabolic panel assesses
• Normal lab value ranges for each part of the panel
• Basic knowledge of the causes of abnormal results on the panel

The metabolic panel is collected through a blood draw in the vein and it assesses:

• Electrolytes
• Renal Function
• Liver function *only the CMP assesses this part

It’s important to point out that exam questions will test you are the normal lab value ranges, and they will give you values that are noticeably abnormal…rather than close to normal. Therefore, if you have the approximate lab range memorized you will be able to recognize the abnormal range.

NOTE: Normal lab value ranges vary among laboratories and sources. For example, one lab or source may say a normal range is 12.5-20.5….while another one may say 10.5-22.5. Therefore, be aware of that when assessing results.

Two ways a physician orders a metabolic panel:

• BMP (Basic Metabolic Panel)
• CMP (Comprehensive Metabolic Panel)

Basic Metabolic Panel assesses:

Glucose, Calcium, Sodium, Chloride, Potassium, CO2, BUN, Creatinine

Comprehensive Metabolic Panel assesses:

Glucose, Sodium, Chloride, Potassium, CO2, BUN, Creatinine PLUS ALP, AST, ALT, Bilirubin, Total Protein, Albumin, Globulin

Metabolic Panel Normal Lab Ranges & Causes of Abnormal Results

*Both the BMP and CMP assesses the following:

Glucose: 70–100 mg/dL (fasting range)….NOT fasting range can extend up to 125 mg/dL

• Measures sugar level in blood
  • Low: HYPOglycemia
    • Causes: too much insulin or diabetic medication
  • High: HYPERglycemia
    • Causes: diabetes, medications likes corticosteroids

Calcium: 8.5–10.5 mg/L

• HYPOcalcemia
  • Causes: parathyroid insufficiency (this gland regulates calcium levels), poor intake of calcium rich foods, low vitamin D levels
• HYPERcalcemia: increase parathyroid activity, high vitamin D intake (vitamin D helps with the absorption of calcium)

Sodium: 135-145 mEq/L

• HYPOnatremia: diarrhea, medications (diuretics: thiazides), renal insufficiency
• HYPERnatremia: hypercortisolism (Cushing’s Syndrome), fluid loss that results in dehydration, renal insufficiency

Chloride: 95-105 mEq/L

• HYPOchloremia: lung disease (emphysema), medications: loop diuretics, diarrhea/vomiting
• HYPERchloremia: renal failure, medications: corticosteroids/diuretics

Potassium: 3.5-5 mEq/L

• HYPOkalemia: medications: loop diuretics and corticosteroids, fluid loss: vomiting, diarrhea, Cushing’s Syndrome (high aldosterone  production causes the kidneys to excrete more potassium which lowers blood levels)
• HYPERkalemia: renal failure, medications: ACE inhibitors, potassium-sparing diuretics, Addison’s Disease (low aldosterone production causes the kidneys to keep more potassium which increase’s blood levels)

Total Carbon Dioxide (CO2): 21-31 mEq/L

• NOTE: Total carbon dioxide in the blood is mainly in the form of bicarbonate. It plays an important role with the acid-base balance in the body. Therefore, a low and high level of total CO2, hence bicarbonate results in:
• LOW: increase acid in blood (metabolic acidosis), diabetic ketoacidosis, aspirin toxicity
• HIGH: lung disease (COPD)

Anion gap: 3 to 10 mEq/L

• This is sometimes listed on the metabolic panel.
• It assesses for acid-base imbalance by looking at certain electrolytes from the metabolic panel (sodium, chloride, potassium, and bicarbonate). It detects the gap or difference between positively and negatively charged electrolytes.
  • HIGH (main cause for concern): metabolic acidosis (DKA, aspirin toxicity, renal failure)

BUN: 5-20

• Measures the blood urea nitrogen: it tells us how well the kidneys are functioning but you also want to look at the creatinine result
  • HIGH (main cause for concern): kidney failure or any disease process that decreases blood flow to the kidneys: shock, heart failure etc.

Creatinine: 0.6–1.2 mg/dL

• Measures the creatinine in the blood, which is a waste product from muscle. Remember the kidneys should normally filter majority of this substance out of the blood. Therefore, it tells us how well the kidneys are filtering the blood. Example: if the creatinine is high, the glomerulus is doing a poor job filtering the blood (which means our kidneys are NOT functioning very well).
• HIGH: kidney failure or there is an issue with the kidney’s function due to variety of problems (lack of perfusion, infection etc.)

eGFR (estimated glomerular filtration rate): >60

• This is also sometimes listed on the metabolic panel.
• It’s the estimation of how well the glomerulus is filtering water, ions, and water from the blood to create urine. It is calculated with the patient’s creatinine level, age, sex, and race to determine
  • <60: renal insufficiency

*Below are areas assessed only by the CMP:

ALP (alkaline phosphatase): 40-120 U/L

• This is an enzyme found in certain organs (bones, liver etc.)
• HIGH: bone or liver disease

ALT (alanine transaminase): 7 to 56 U/L & AST (aspartate transaminase) 10-40 U/L

• These are enzymes found in organs.
  • AST: found mainly in the heart and liver
  • ALT: found mainly in the liver and kidneys
  • These levels should be low, but if elevated it could mean there is liver damage.

Bilirubin: 0.1-1 mg/dL (less 1)

• It’s a waste product from the breakdown of RBCs. When red blood cells break down it creates an orangish/yellowish substance. This function is mainly performed in the liver, and this substance is excreted in the bile, which is then excreted in the stool. Bilirubin gives stool its brown color and there should be VERY little in the urine.
• You can just look at a patient and tell if the bilirubin is high. HOW? The patient’s skin will have an orange hue to it, the mucous membranes like the sclera will be yellow, and the urine will turn orangish yellow. This is termed as jaundice.

• • HIGH: elevated in people who have liver disease or some type of GI problems like a bile duct blockage etc.

Total Protein: 6.2–8.2 g/dL

• Measures the complete amount of proteins in the blood like: albumin and globulin
• LOW: not producing enough in the liver or losing it (ex: kidney failure)
• HIGH: cancer

Globulin: 2-4 g/dL

• Made in liver by immune system. These proteins help fight infection and help assess liver function…elevated: immune problem (cancer), infection etc.

Albumin: 3.4–5.4 g/dL

• It’s a protein made by the liver.
• It plays a big role with regulating oncotic pressure inside blood vessels so they don’t leak….low levels cause vessels to leak and can lead to swelling.

Test your knowledge with the Metabolic Panel Quiz.

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