This series follows along with our Lab Values Flashcards which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.
In your nursing practice you will encounter a variety of lab panels, including CBC, BMP, and liver function; which are covered in THIS video and article, and CMP, lipid panel, thyroid panel; which are covered in our next video, Lab Panels - CMP, Lipids, Thyroid Panel. As a nurse, it's important to understand what each of the tests means, what the components of each panel are, and what information you can get from that panel. As Meris shares in the video, she sometimes gets feedback from nurses along the lines of, "it's not my job to know this panel, it's the provider's."
While it's definitely true that it is the provider's job to know which tests are in which panel, when to order them, and why—it's also true for nurses that knowing what the lab panels mean helps you advocate for your patient—nurses should be empowered to question orders when needed, and also to answer questions patients might have about these panels.
Complete blood count (CBC)
A complete blood count is what it sounds like—it is counting the components of your blood. A complete blood count includes:
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Hemoglobin (Hgb)
- Hematocrit (Hct)
- Platelets
Red blood cells (RBCs) in a CBC
Red blood cells are one of the components measured in a CBC, and this includes how many there are, what size they are, what shape they are, and whether they have a nucleus or not.
White blood cells (WBCs) in a CBC
White blood cells are a key part of the immune system that help the body fight infection and disease. White blood cells are one of the components counted in a CBC, which can help to identify if the patient is experiencing an infection.
The expected range for WBCs is 5,000 - 10,000/mm³.
Low white blood cell count (under 4,000/mm³) is called leukopenia and can be caused by autoimmune diseases, bone marrow suppression, or drug toxicity.
High white blood cell count (over 10,000/mm³) is called leukocytosis and can be caused by infection or inflammation.
Hemoglobin (Hgb) in a CBC
Hemoglobin is the iron-rich protein in red blood cells that carry oxygen.
The expected female Hgb range is 12 - 16 g/dL and the expected male Hgb range is 14 - 18 g/dL.
Low levels of hemoglobin can be caused by anemia, hemorrhage, or kidney disease. High levels of hemoglobin can be caused by COPD, severe dehydration, or polycythemia.
Hematocrit (Hct) in a CBC
Hematocrit is the percentage of the blood made up of red blood cells.
The expected female Hct range is 37 - 47% and the expected male Hct range is 42 - 52%.
Lower levels of hematocrit can be caused by anemia, hemorrhage, or kidney disease. Higher levels of hematocrit can be caused by COPD, polycythemia, hypovolemic shock, or severe dehydration.
H&H panel vs. CBC
Meris notes in the video that hemoglobin and hematocrit might be tested on their own, as a sort of mini-panel that can be referred to as an "H&H." Meris provides the example of a patient that's bleeding — they may need their hemoglobin and hematocrit checked every four hours, but not the entire CBC.
So, an H&H covers hemoglobin and hematocrit, while a CBC covers those two, plus RBCs, WBCs and platelets.
Platelets in a CBC
Platelets are blood cell fragments used to form clots in the body to stop bleeding.
The expected adult range for platelets is 150,000 - 400,000 mm³.
Low levels of platelets (under 150,000 mm³) is called thrombocytopenia and causes can include hemorrhage, leukemia, and splenomegaly (large spleen). Low platelets mean a high risk of bleeding!
High levels of platelets (over 400,000 mm³) is called thrombocytosis and causes can include polycythemia, inflammatory diseases (e.g., rheumatoid arthritis, irritable bowel disease), infection, cancer, or splenectomy.
CBC with differential
A CBC with differential is the same panel as a regular CBC, but it also includes the specific amounts of different types of white blood cells. So this is what's measured in a CBC with differential:
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Neutrophils
- Lymphocytes
- Monocytes
- Eosinophils
- Basophils
- Hemoglobin (Hgb)
- Hematocrit (Hct)
- Platelets
It's called a differential because the white blood cell types are differentiated from one another rather than just a total number.
Why differentiate the types of white blood cells? Because a high overall white blood cell count can tell you that a patient is fighting infection, but it provides no information about what type—including the counts of the specific types of white blood cells can provide information on what type, source, or longevity of infection the body may be experiencing.
Basic metabolic panel (BMP)
A basic metabolic panel, which is also sometimes referred to as "a chemistry," is a lab panel that measures electrolyte levels, glucose, kidney function, and carbon dioxide. Here's a list of what's measured in a BMP:
- Electrolyte levels
- Sodium (Na)
- Calcium (Ca)
- Potassium (K)
- Chloride (Cl)
- Glucose level
- Kidney function
- Creatinine
- Blood Urea Nitrogen (BUN)
- Glomerular filtration rate (GFR) may be included depending on the facility
- Carbon dioxide (CO₂)
Electrolyte levels in a BMP
The electrolyte levels that are measured in a basic metabolic panel include sodium, calcium, potassium, and chloride.
Sodium (Na) in a BMP
Sodium, which uses the symbol Na, is one of the electrolytes tested in a basic metabolic panel, and it's an important electrolyte for nerve and muscle function as well as fluid volume maintenance.
The expected range for Sodium (Na) on a BMP is 136 - 145 mEq/L.
Low levels of sodium (under 136 mEq/L is called hyponatremia and can be caused by diuretics, kidney failure, diaphoresis, SIADH, hyperglycemia, heart failure, fluid volume overload (dilutional hyponatremia). Symptoms of hyponatremia include confusion (which can be more common in elderly patients), fatigue, nausea and vomiting, headache, and seizures.
High levels of sodium (over 145 mEq/L) is called hypernatremia and can be caused by kidney failure, excess sodium intake, Cushing's syndrome, diabetes insipidus, fever, or an NPO diet. Symptoms of hypernatremia include thirst, lethargy, confusion, gastrointestinal upset, muscle twitching, seizures, or irritability and agitation.
Calcium (Ca) in a BMP
Calcium, which uses the symbol Ca, is one of the electrolytes tested in a basic metabolic panel, and it's an electrolyte important for bone and teeth formation, nerve and muscle function, and blood clotting.
The expected range for Calcium (Ca) on a BMP is 9 - 10.5 mg/dL.
Low levels of calcium (under 9.0 mg/dL) is called hypocalcemia, and it can be caused by hypoparathyroidism, acute pancreatitis, or vitamin D deficiency.
Symptoms of hypocalcemia include a positive Chvostek’s sign, a positive Trousseau’s sign, muscle spasms, and paresthesia (a burning/prickling sensation).
High levels of calcium (over 10.5 mg/dL) is called hypercalcemia, and it can be caused by hyperparathyroidism, cancer, prolonged immobility, or long-term corticosteroid use.
Symptoms of hypercalcemia include kidney stones, gastrointestinal upset, constipation, bone pain, muscle weakness, or confusion.
Potassium (K) in a BMP
Potassium, which uses the symbol K, is one of the electrolytes measured on a BMP and it's an electrolyte important for maintenance of intracellular fluid, and regulation of heart and muscle contractions.
The expected range of Potassium (K) on a BMP is 3.5 - 5.0 mEq/L.
Low levels of potassium (under 3.5 mEq/L) is called hypokalemia and causes can include diuretics (e.g., furosemide), gastrointestinal losses, Cushing’s syndrome, metabolic alkalosis.
Symptoms of hypokalemia can include dysrhythmias, muscle weakness, constipation/ileus, hypotension, weak pulses.
High levels of potassium (over 5 mEq/L) is called hyperkalemia and causes can include diabetic ketoacidosis (DKA), metabolic acidosis, salt substitutes, kidney failure.
Symptoms of hyperkalemia can include dysrhythmias, muscle twitching/weakness, paresthesia, or diarrhea.
Chloride (Cl) in a BMP
Chloride, which uses the symbol Cl, is one of the electrolytes measured on a BMP and it's an electrolyte important for maintenance of fluid balance; it's also a component of digestive juices.
The expected range for Chloride (Cl) on a BMP is 98 - 106 mEq/L.
Low levels of chloride (under 98 mEq/L) is called hypochloremia and causes can include metabolic alkalosis, gastrointestinal losses (e.g., because of vomiting or NG suctioning), diuretics, or heart failure.
Symptoms of hypochloremia can include weakness, fatigue, dyspnea, confusion.
High levels of chloride (over 106 mEq/L) is called hyperchloremia and causes can include metabolic acidosis, dehydration, or excess salt intake.
Symptoms of hyperchloremia can include weakness, fatigue, thirst, or muscle cramps.
Glucose level in a BMP
Glucose is one of the values measured in a BMP.
If the test is performed while fasting the blood sugar is expected to be < 100 mg/dL. However this test may be performed during times when a patient hasn’t been fasting, such as in the emergency room. In that case, it is expected for the blood glucose to be somewhat elevated. It is important to ask your patient when the last time they had something to eat or drink was, so the glucose result can be considered within the context of their last oral intake.
Kidney function in a BMP
Creatinine in a BMP
Creatinine is one of the kidney function values measured in a BMP, and it's a waste product created from the normal breakdown of muscles in the body.
The expected range of creatinine on a BMP is 0.6 - 1.2 mg/dL
High creatinine (over 1.2 mg/dL) indicates the presence of kidney dysfunction.
Creatine is more specific to kidney function than BUN.
Blood Urea Nitrogen (BUN) in a BMP
Blood Urea Nitrogen (BUN) is nitrogen in the blood from the waste product urea, which is produced when protein is broken down in the body.
The expected range for BUN on a BMP is 10 - 20 mg/dL
High BUN (over 20 mg/dL) can be caused by kidney disease, dehydration, or conditions that decrease blood flow to the kidneys like CHF, AKI, or shock.
Glomerular filtration rate (GFR) in a BMP
Depending on the facility, glomerular filtration rate (GFR) might be measured in a BMP. GFR is a measurement of how much blood passes through the glomeruli each minute, which can provide information about kidney function.
The expected range for GFR is greater than or equal to 90 mL per minute.
Carbon dioxide (CO₂) in a BMP
Carbon dioxide is a byproduct of cellular respiration, which means it's related to metabolism, which is why it's measured in a basic metabolic panel. This is a venous level of carbon dioxide, as opposed to the partial pressure of carbon dioxide that is measured in an arterial blood gas.
Liver function panel
A liver function panel, sometimes called LFTs for liver function tests, is a set of tests that provides information on liver function by measuring protein, byproducts and enzymes. Here's a list of what's measured in a liver function panel:
- Total protein
- Albumin
- Bilirubin
- Liver enzymes
- Alkaline phosphatase (ALP)
- Alanine aminotransferase (ALT)
- Aspartate aminotransferase (AST)
Total protein in a liver function panel
Total protein is one of the values measured in a liver function panel, and it's the total amount of albumin and globulin in the fluid portion of the blood.
The expected range for total protein in a liver function panel is 6.4 - 8.3 g/dL.
Low total protein (under 6.4 g/dL) can be caused by liver disorders, malnutrition, kidney dysfunction, celiac disease, or inflammatory bowel disease.
Albumin in a liver function panel
Albumin is another value measured in a liver function panel, and it's a protein made by the liver, important for transport of substances and synthesis of other proteins. An albumin level reflects a patient's long-term nutritional status. It's essential for keeping fluid in the bloodstream.
The expected range for albumin on a liver function panel is 3.5 - 5 g/dL.
Low albumin (under 3.5 g/dL) can be caused by liver disease, kidney disease, or malnutrition. Low albumin levels can lead to edema, fatigue, and weakness.
Bilirubin in a liver function panel
Bilirubin is one of the values measured in a liver function panel, and it's a yellow substance found bile that's produced during the breakdown of red blood cells.
The expected range of bilirubin on a liver function panel is 0.3 - 1 mg/dL. The expected range for direct (conjugated) bilirubin is 0.1 - 0.3 mg/dL. The expected range for indirect (unconjugated) bilirubin is 0.2 - 0.8 mg/dL
Liver enzymes in a liver function panel
The liver enzymes measured in a liver function panel are ALT, AST, and ALP. If these are elevated, it is indicative of liver dysfunction, including cirrhosis, or hepatitis.
Alanine aminotransferase (ALT) in a liver function panel
ALT is an enzyme produced by the liver, important in metabolism.
The expected range for ALT in a liver function panel is 4 - 36 units/L. High levels of ALT can be caused by liver dysfunction, like hepatitis or cirrhosis. ALT is more specific to the liver than AST.
Aspartate aminotransferase (AST) in a liver function panel
AST is an enzyme found mostly in the liver, but also in the muscles.
The expected range for AST in a liver function panel is 0 - 35 units/L. High levels of AST (over 35 units/L) can be caused by liver dysfunction, like hepatitis or cirrhosis or other tissue damage in the body, like the heart or skeletal muscle.
